How to use Safe Mode Option in computers repairs

Practical Uses for Safe Mode

If you are unable to start your system by using Last Known Good Configuration, Windows XP Professional, Windows 2000 and Windows Server 2003 provides safe mode, a startup option that disables startup programs and nonessential services to create an environment useful for troubleshooting and diagnosing problems. In safe mode, Windows XP/2000/2003 starts a minimal set of drivers that the operating system needs to function. Support for devices such as audio devices, most USB devices, and IEEE 1394 devices is disabled to reduce the variables that you need to account for when diagnosing the cause of startup problems, Stop messages, or system instability.

Logging on to the computer in safe mode does not update Last Known Good Configuration information. Therefore, if you log on to your computer in safe mode and then decide you want to try Last Known Good Configuration, the option to do so is still available.

Essential drivers and system services enabled in safe mode include the following:

• Drivers for serial or PS/2 mouse devices, standard keyboards, hard disks, CD-ROM drives, and standard VGA devices. Your system firmware must support universal serial bus (USB) mouse and USB keyboard devices in order for you to use these input devices in safe mode.
• System services for the Event Log, Plug and Play, remote procedure calls (RPCs), and Logical Disk Manager.

When do you need to use Safe Mode

Enabling only components needed for basic functionality allows the operating system to start in the following situations:

• The computer consistently stops responding: You can restart the operating system in safe mode and use the tools described in this appendix to diagnose and resolve problems.
• The computer starts with a blank or distorted video display: You can start your computer in safe mode and then use Control Panel to select video adapter settings that are compatible with your monitor. New settings take effect when you restart the computer.
• The computer does not start normally after you install new hardware or software: If recently installed hardware or software prevents you from starting Windows XP Professional in normal mode, you can use safe mode to uninstall software, or to remove or roll back device drivers.
• The computer is infected with virus or Trojan, which is residing in the system configuration. Since Windows use the files considering them as essential part of the normal system configuration, you are not able to clean or get rid of them. The files and drivers that are considered “in use” by operating system are blocked from any accidental or intentional modifications. So, Many forms of malicious software will protect or reinstall themselves constantly if they are allowed to start in the first place. These programs will situate themselves in one of the many autorun locations in the Windows registry and file structure. When Windows is started normally, so is the offending software, running as a process in the background. When you start the PC in Safe Mode, these autorun locations are not used, and no software is started automatically. This can allow virus and spyware removal programs the opportunity they need to remove the malicious software completely. If you are having virus or spyware problems on your PC, you should always run antivirus and anti-spyware programs in Safe Mode to ensure that they have maximum effect.

Safe mode helps you diagnose problems. If a symptom does not reappear when you start in safe mode, you can eliminate the default settings and minimum device drivers as possible causes. If a newly added device or a changed driver is causing problems, you can use safe mode to remove the device or reverse the change.

There are circumstances where safe mode will not be able to help you, such as when Windows system files that are required to start the system are corrupted or damaged. In this case, the Recovery Console may help you.

Safe Mode also bypasses startup programs. Bypassing startup programs reduces system complexity and enables you to see whether a startup program is the source of the problem.

In safe mode, the operating system does not run network-based startup programs. To enable network logon scripts in safe mode, select Safe Mode with Networking on the Windows Advanced Options Menu.

How to start your computer in safe mode

1. Remove all floppy disks and CDs from your computer, and then restart your computer.
2. When prompted, press F8. If Windows XP Professional starts without displaying the Please select the operating system to start menu, restart your computer. Press F8 after the firmware POST process completes, but before Windows displays graphical output.
3. From the Windows Advanced Options Menu, select a safe mode option listed in the following list:

• Safe Mode (SAFEBOOT_OPTION=Minimal): This option uses a minimal set of device drivers and services to start Windows.
• Safe Mode with Networking (SAFEBOOT_OPTION=Network): This option uses a minimal set of device drivers and services to start Windows together with the drivers that you must have to load networking.
• Safe Mode with Command Prompt (SAFEBOOT_OPTION=Minimal(AlternateShell)): This option is the same as Safe mode, except that Cmd.exe starts instead of Windows Explorer.
• Enable VGA Mode: This option starts Windows in 640 x 480 mode by using the current video driver (not Vga.sys). This mode is useful if the display is configured for a setting that the monitor cannot display.
  Note Safe mode and Safe mode with Networking load the Vga.sys driver instead.
• Last Known Good Configuration: This option starts Windows by using the previous good configuration.
• Directory Service Restore Mode: This mode is valid only for Windows-based domain controllers. This mode performs a directory service repair.
• Debugging Mode: This option turns on debug mode in Windows. Debugging information can be sent across a serial cable to another computer that is running a debugger. This mode is configured to use COM2.
• Enable Boot Logging: This option turns on logging when the computer is started with any of the Safe Boot options except Last Known Good Configuration. The Boot Logging text is recorded in the Ntbtlog.txt file in the %SystemRoot% folder.
• Starts Windows Normally: This option starts Windows in its normal mode.
• Reboot: This option restarts the computer.
• Return to OS Choices Menu: On a computer that is configured to starting to more than one operating system, this option returns to the Boot menu.

To highlight the Safe Mode operations on Windows versus normal operation, user gets the initial disclaimer on the special conditions of running computer in Safe Mode, and the Safe Mode markers are present all the way on the corners of your screen.

Use Msconfig to get to Safe Mode

If you only want to enter Safe Mode occasionally and have trouble using the F8 key, you can use the System Configuration Utility (msconfig). Go to Start|Run and enter “msconfig” (without quotes). When the utility opens, click on the tab BOOT.INI as shown in the figure below.

Highlight the operating system listed in the section [operating systems] as shown in the figure below. Next put a check by the entry /SAFEBOOT as shown below. Also click the radio button MINIMAL Then reboot. The system should open in Safe Mode. When finished using Safe Mode, open Msconfig again and remove the check by /SAFEBOOT. Otherwise, you will continue to open in Safe Mode whenever you boot.

How to start your computer normally after using Safe Mode

1. Shut down the computer and allow it to restart
2. By default, it will start in Normal Mode

Sources and Additional Reading:
http://www.petri.co.il/safe_mode_in_windows_2000_xp_2003.htm
http://support.microsoft.com/kb/315222
http://www.computer-2tr.com/tips/05/20050113.html
http://vlaurie.com/computers2/Articles/safemode.htm

How to Optimize Computer Performance with Hard Drive Defragmentation?

Hard Drive Performance Optimization

Windows comes with a collection of house cleaning tools, including ScanDisk, Disk Defragmenter and Disk Cleanup, to help keep your disk in peak working order.

Why should you bother with the housework? A couple of reasons. First, disks are hard working, mechanical devices and, like all mechanical devices, prone to failure. A little preventative maintenance can warn you of potential problems and fix minor glitches before they can do damage to your data.

Second, the way files are organized on your drive has a perceptible impact on the performance of your computer. If your files are stored neatly, end-to-end, without fragmentation, reading and writing to the disk is speedier.

What is file fragmentation?

Sometimes when you install a program or create a data file, the file ends up chopped up into chunks and stored in multiple locations on the disk. This is called fragmentation.

What makes this happen?

When you first install your operating system and programs on your hard disk, they are written to the disk, for the most part, in one contiguous block without any gaps. The exceptions are certain system files that must be stored in specific locations. Over time, as you create and then delete documents or uninstall programs, once-filled locations are left empty and you end up with files dotted all over the disk.

Now, when Windows is writing a file to the disk, it looks for a suitable piece of free space in which to store it. What happens, then, when you copy a 40 MB database or audio file to the disk and the biggest slice of free space is only 30 MB? Or say you modify an existing file, appending a whole bunch of data so the file now takes up more space on the disk. To accommodate the files, Windows writes the first part of the file in one section of the disk and then scouts around for other places to store the rest of the file. The end result is that a single file may be stored in several chunks scattered about the disk.

Of FAT and files

Windows keeps track of each file’s location in the File Allocation Table, or FAT (Windows 98 and Me use a file system called FAT32). When your file is written to disk, FAT32 provides Windows with the address of an unoccupied disk cluster. FAT32 also tells Windows on which disk sectors it will find that cluster; that is, it provides the physical location of the cluster. This information is used by your PC’s BIOS (the Basic Input/Output System) to direct the actual disk writing operation.

If the file is too large to fit in a single cluster, Windows asks FAT32 for another vacant cluster, and another, and another until the whole file is written to disk. If you have lots of free clusters side by side, FAT32 can point Windows to an adjacent series of clusters, resulting in a file which occupies one contiguous chunk of the disk. If no adjacent cluster is available, FAT32 tracks down a space elsewhere on the disk and tells Windows to put the next bit of the file there; and so on until the full file is written to disk.

A record of the clusters used for storing the file is kept by FAT32 so Windows can find the file once more when you want to read it.

The fragmentation penalty

Although this all happens quickly, it makes a lot of work for your hard disk. Its read/write head, which moves across the drive platter from location to location transferring data, has to zip all over the place when saving or opening a single highly fragmented file. (By the way, many disks have more than one read/write head and multiple platters.) If a file is unfragmented, the disk head moves to one location, reads the file in one sequential swoop, and that’s it.

A file stored in, say, four fragments, can easily take twice as long to open as the same file unfragmented, although the actual performance hit you take is affected by other factors, including the total size of the file.

The techniques used by the Disk Defragmenter

# Moving all the index or directory information to one spot. Moving this spot into the center of the data, i.e. one third of the way in, so that average head travel to data is halved compared to having directory information at the front.
# Moving infrequently used files further from the directory area.
# Obeying a user provided table of file descriptions to emphasize or ignore.
# Making files contiguous so that they can be read without unnecessary seeking.

Windows XP Disk Defragmenter Limitations

Disk Defragmenter in Windows XP has the following MAJOR limitations:
# It does NOT defragment files residing in the Recycle Bin.
# It also cannot defragment "in-use" files.
# Does not defrag and clean the registry.
# It can defragment only local volumes.
# It can defragment only one volume at a time.
# It cannot defragment one volume while it is scanning another.
# It cannot be scheduled automatically. If you need to schedule disk defragmentation, use the Defrag.exe command line tool.

Defragment Your Disk Drive Volumes in Windows XP

Disk Defragmenter Microsoft Management Console (MMC) is based on the full retail version of Executive Software Diskeeper. The version that is included with Windows XP and later provides limited functionality in maintaining disk performance by defragmenting volumes that use the FAT, FAT32, or NTFS file system.
To start Disk Defragmenter MMC, use one of the methods.

Method 1: Use the Properties of Your Local Disk

1. Open My Computer.
2. Right-click the local disk volume that you want to defragment, and then click Properties.
3. On the Tools tab, click Defragment Now.
4. Click Defragment.
5. If you have more than one hard disk, repeat this process for each hard disk listed.

Method 2: Use Computer Management MMC

1. Start Computer Management MMC (Compmgmt.msc).
2. Click Disk Defragmenter.
3. Click the volume that you want to defragment, and then click Defragment.

Method 3: Use Disk Defragmenter MMC.

1. Start Disk Defragmenter MMC (Dfrg.msc).
2. Click the volume that you want to defragment, and then click Defragment.

It May Take a While

The Disk Defragmenter tool can take anywhere from minutes to hours to run, depending on the size of your hard drive and also how fragmented the drive is. One way to run the Disk Defragmenter and not lose any computing time is to leave the system and run the Disk Defragmenter during a time when the system can be left on but is not be in use (e.g., 3 or 4 a.m.). You can simply use the steps above to launch Disk Defragmenter when your computing tasks are done for the day or you can have the Windows Task Scheduler automatically run the Disk Defragmenter on a certain day and time each week or month.

Tips for Getting the Best Results

• Ensure you have no applications running when you start the Disk Defragmenter. If you system is accessing applications the Defragmenter will not stay running. Be sure to turn off your screensaver also.
• Delete your Temporary Internet Files and other files you do not use. You can also uninstall unused programs. In the Properties tab of your hard drive you can access "Disk Cleanup," which will help you get rid of unused and unnecessary files.
• Run the Disk Defragmenter at regular intervals. However you can also run the tool if you add a lot of files to the disk at one time or find you are running low on disk space.
• The volume must have at least 15% free space for Defrag to completely and adequately defragment it. Defrag uses this space as a sorting area for file fragments. If a volume has less than 15% free space, Defrag only partially defragments it.

Automatic Defragmentation Scheduling with Task Scheduler

1. Open Control Panel, double-click Scheduled Tasks
2. Double-click Add Scheduled Task
3. On the Scheduled Task Wizard dialog, click Next.
4. Click Browse and navigate to windows’system32 folder. Select defrag.exe and click Open. In the Scheduled Task Wizard dialog, type a name for the scheduled task (for example type Disk Defrag).
5. Under Perform this task, select how often you wish Disk Defragmenter to run. Click Next.
6. Set the time at which you wish the Disk Defragmenter scheduled task to run. This should be a time when your computer is turned on but not under heavy use (i.e. at night time). Select the frequency at which you want the Disk Defragmenter task to run (Every Day, Weekdays, or Every <N> days, where <N> is the number of days between scheduled runs). Click Next.
7. Enter a user name under which the Disk Defragmenter scheduled task will run. This user must be an administrator on the local machine (see note above). Enter the password for that user and confirm it. Click Next.
8. Check Open advanced properties for this task when I click Finish, and click Finish.
9. In the Run text box, you can see the full path and command for defrag.exe.  Add the drive letter for the drive you wish to defragment to the command in the Run text box. If you want to defragment drive C:, your Run command should look like this: C:’WINDOWS’SYSTEM32’defrag.exe C: Click OK.
10. In the Set Account Information dialog, enter and confirm the password for the user listed in Run as and click OK.
11. Task Scheduler will automatically run Disk Defragmenter with the settings you selected at the time you selected.

Only one instance of Disk Defragmenter can be running at any given time. If you have multiple partitions you’ll need to add a separate scheduled task for each one, and make sure you give each task a different starting time, allowing for the previous one to finish.

Defrag Your Boot Files

File fragmentation can happen at start-up too. A real power tip (not for beginners) is to have Windows XP automatically defragment these files, but you will have to make sure your Windows XP registry has the correct setting.

Open your Registry Editor and go to key:
HKEY_LOCAL_MACHINE’SOFTWARE’Microsoft’Dfrg’BootOptimizeFunction
Look for a VALUE in the right hand pane called BootOptimizeFunction
...if it does NOT exist, choose from the menu Edit > New > String Value and create it.
Make sure that it has the entry Y.


Sources and Additional Information:
http://www.geekgirls.com/windows_defrag.htm
http://support.microsoft.com/kb/314848
http://www.webopedia.com/DidYouKnow/Computer_Science/2008/disk_defragmentation.asp
http://www.petri.co.il/schedule_disk_defrag_to_run_automatically_in_windows_xp_2003.htm
http://www.updatexp.com/disk-defragmenter.html

Magnetic Recording

Data is written and read as a series of bits, the smallest unit of digital data. Bits are either a 0 or a 1, or on/off state if you prefer. These bits are represented on a platter’s surface by the longitudinal orientation of particles in the magnetically sensitive coating that are changed (written) or recognized (read) by the magnetic field of the read/write head. Data isn’t just shoveled onto a hard drive raw, it’s processed first, using a complex mathematical formula. The drive’s firmware adds extra bits to the data that allow the drive to detect and correct random errors.

Rapidly replacing longitudinal magnetic recording in new drive manufacture is a process called perpendicular magnetic recording. In this type of recording, the particles are arranged perpendicular to the platter’s surface. In this orientation they can be packed closer together for greater density, with more data per square inch. More bits per inch also means more data flowing under the read/write head for faster throughput.

Information is written to and read from both sides of the platters using mechanisms mounted on arms that are moved mechanically back and forth between the center of the platter and its outer rim. This movement is called seeking, and the speed at which it’s performed is the seek time. What the read/write heads are seeking is the proper track--one of the concentric circles of data on the drive. Tracks are divided up into logical units called sectors. Each sector has its own address (track number plus sector number), which is used to organize and locate data.

In the event a drive’s read/write head doesn’t arrive at the track it’s seeking, you may experience what’s called latency or rotational delay, which is most often stated as an average. This delay occurs before a sector spins underneath the read/write head, and after it reaches the proper track.

Source: http://www.pcworld.com/article/18693/how_it_works_hard_drives.html