You have what's known as a restore CD. This bootable CD will restore your system to how you originally bought it (ie it will wipe all the things you have done since buying it). The most important thing on your computer is the data so this should be backed up very regularly (whether it is to floppy diskette, CD or DAT tape). When disasters strike you can restore your system using the restore CD and the backed up data. The ASR will allow you to repair your Windows XP installation (ie if you can't boot properly) even when the "boot to safe mode" or "boot to the last known good" does not work.