If for some reason your copy of Windows XP is not starting properly, or you're having problems with a device driver, you can start Windows in 'Safe Mode'. This mode is also useful for removing malicious software that automatically loads into memory when your computer starts, such as viruses and spyware. In Safe Mode, only a minimal version of the OS will be loaded into memory, all non-essential drivers, services, and startup applications will not be loaded.
The easiest way to enter into Safe Mode is by pressing the F8 key during your computer's startup process. You need to start pressing this key quickly after your comptuer's BIOS screen disappears. If Windows starts loading, you missed your opportunity to enter into Safe Mode.
After you press the F8 key you will enter into the Start up screen, from here you can select Safe Mode or one of the other startup menu options (such as: command prompt, command prompt with networking, or normal with logging). These other start-up modes are useful for debugging problems with your computer's booting.