Safe mode function is useful when you have problems on your computer and you cannot fix them. If you cannot access control panel to fix a problem, in safe mode you will be able to use control panel.
Safe mode is used when some programs that are required in order to fix a problem are no longer working. In safe mode all basic and essential programs work normally.
Depending on your machine (windows version), you need to follow these step-by-step easy instructions.
If you have:
Microsoft Windows XP Professional or Windows Vista
Step 1
When switching on the computer you usually see a black screen. Just before you see the Windows Screen, press F8 key on your keyboard.
The Windows Screen is the blue screen which has the Microsoft Logo. If Windows launches before you press F8 you can restart computer again and redo.
Step 2
Use the arrow keys to highlight the safe mode option, and then press ENTER.
Now in Safe mode you have a limited set of options. People usually use Safe Mode to fix some computer problem. For additional information email us your problem if it is related to spyware or other critical infection.
If you have:

Windows 95, 98 or Me
Same instructions like Windows XP users above.
If you have:

Windows 2000
Switch on your computer.
When you see the black-and-white Starting Windows bar at the bottom of the screen, press F8 key on your keyboard. An options menu appear where you will be able to choose Safe Mode Option.
Important Note:
If your computer is already switched on first shut down the computer. Turn off the power. Wait 30 seconds and then switch on your computer.
That is how to start your computer in Safe Mode. This is a very helpful shortcut in case you cannot start your computer because of some problems. You will be able to repair the damage in safe mode. Then restart your computer again as normal.