and for the most part there is nothing the average user would have to do. You can take a peek at the System Restore tab in System properties to see some of the variables available to you.

Backing up data is a wide open subject which can be as simple as copying files to a floppy to drive imaging software.

XP includes a Backup utility in its Accessories folder, again this is usually enough for the average users needs. The key in any backup is redundancy. More then one copy in a different media (USB flash drive, CDRW, DVDRW, external hard drive) is best.