Q: How do I do it ? I have an XP laptop
A: You could run a system restore, which restores your factory setting to a date specified by you. Secondly, if you have your O/S installation disks, you could restore your O/S to its original state. System Restore: START > All Programs > Accessories > System Tools > System Restore (After selecting a date to restore your machine to, you will need to restart your PC) Restore of O/S: Insert your installation disk in your disk drive, as you machine is "booting" up, keep hitting the 'F8" key. You should then select the "Boot from CD" option. Then follow the instructions to REPAIR your O/S. (Restore)