What is System Restore on Windows XP systems?
System Restore is a service that runs in the background, continually monitoring changes in files, folders, and settings that are critical to the proper operation of your computer. It will take regular snapshots of your systems registry. If you encounter a problem with your system, or suspect a major virus / spyware infestation just occurred, you can use this tool to roll your computers settings back to a previous date where your computer was (hopefully) working properly. Not all files / folders are protected / fixed if you use System Restore. Your data, documents, and email files / folders are not monitored so System Restore does NOT replace a regularly scheduled and run backup of your computer. It can help you in an emergency though.
