System Restore is a feature built into Windows XP and Windows ME that allows users to 'roll-back' to specific restore points without affecting data files. A restore point is automatically created (as long as System Restore is turned on) when new software and/or drivers are installed. If there is a problem with the installation System Restore allows a user to select a restore point (a date) to revert back to. The problem here is this, if a computer is infected with viruses, spyware and/or adware when a restore point is created, rolling-back to that restore point will re-infect the computer.

That's why one of the first things I do after realizing a computer is infected with malware is to disable system restore, then I re-scan the computer with anti-virus software, and anti-spyware software, remove any problems discovered and turn system restore back on once the computer is virus and spyware free. Read on for a step-by-step on how to disable system restore.
 

Windows XP

• click Start
• click Control Panel
• click System
• click the System Restore tab
• un-check the box that reads Turn off System Restore on all drives
• to turn System Restore on put a check back in the box

another method...

• click Start
• right click on My Computer
• select Properties
• click the System Restore tab
• un-check the box that reads Turn off System Restore on all drives
• to turn System Restore on put a check back in the box

yet another method (and I am sure there are many more!)...

• click Start
• click All Programs
• click Accessories
• click System Tools
• click System Restore
• un-check the box that reads Turn off System Restore on all drives
• to turn System Restore on put a check back in the box

Windows ME

• right click on My Computer select Properties
• select the Performance tab and click File System
• select the Troubleshooting tab and click to check the box for Disable System Restore
• click Ok twice, and Yes when prompted to restart your computer
• to turn System Restore on follow these steps again, this time click to clear the box for Disable System Restore