Log on to Windows as Administrator.
Click Start, point to All Programs, point to Accessories, point to System Tools, and then click System Restore. System Restore starts.
On the Welcome to System Restore page, click Undo my last restoration, and then click Next.
Note: A System Restore message may appear that lists configuration changes that System Restore will make. Click OK.
On the Confirm Restoration Undo page, click Next. System Restore restores the original Windows XP configuration, and then restarts the computer.
Log on to the computer as Administrator. The System Restore Undo Complete page appears.
Click OK.