System Restore is a feature of Microsoft Windows XP that automatically saves a copy of important system settings and files so that you can easily restore those settings if something goes wrong. System Restore creates a backup copy every day and every time you install new hardware or software.
You should use System Restore only after you have tried other troubleshooting techniques to fix the problem you may be having with a hardware or software program. System Restore simply returns your system to the way it was before you installed the hardware or software—it doesn’t fix your hardware or software problem. Once you’ve restored your system, you’ll have to start the troubleshooting process again with the new software or hardware
Strat System restore process
Click Start>Accessories>System Tools>System Restore
The System Restore Wizard opens. On the Welcome to System Restore page, make sure Restore my computer to an earlier time is selected, and then click Next.
On the Select a Restore Point page, click the date on the calendar that you want to restore your computer to. Choose the last date when everything was working properly—before you made configuration changes, installed new software, or added new hardware. Then, click Next.
On the Confirm Restore Point Selection page, click Next.
The System Restore Wizard shuts down Windows XP and restores your settings. Then, it restarts Windows XP and displays the Restoration Complete message. Click OK.
That’s it Now that you have restored your system settings to an earlier state, test your computer to determine whether the problem was resolved.