A restore point is a saved "snapshot" of a computer's data at a specific time. Restore points are a component of the Windows System Restore utility. By creating a restore point, you can save the state of the operating system and your own data so that if future changes cause a problem, you can restore the system and your data to the way it was before the changes were made. When a restore point is established, your computer creates a backup copy of all data at that particular time. The possible types of restore points are: system checkpoints, which are scheduled restore points that your computer creates; manual restore points, which the user creates; and installation restore points, which are automatically created when you install certain programs.
It's a good idea to create a restore point before you make any changes to your computer that could potentially cause problems or make the system unstable. When you run the System Restore utility, it displays a calendar that lists the restore points created (every day that your computer is used will have at least one restore point and some may have several, depending on usage). Even if you haven't manually created a restore point, you can specify restore points that have been automatically created. If you get in trouble, you just select a restore point that predates the difficulty, and System Restore will undo any changes since then. Windows XP creates a restore point each time: an unsigned device driver or a System Restore-compatible application is installed; Windows Update is run; or an earlier restore point is restored.Content Continues Below
To create or choose a restore point in Windows XP: from the Start menu, select Programs > Accessories > System Tools > System Restore. From the System Restore window you can select Restore my computer to an earlier time or Create a restore point. If you choose the first option, you will be able to select a restore point that is already stored in your computer. If you choose the second option, you will be asked to give the restore point a descriptive name to help you identify it, and the utility will back up all the data and save it with the restore point's name, and the time it was created. Then, if need be, you can select this restore point in the future by following the same route, and choosing the option to restore your computer to an earlier time.