Make sure you make your recovery DVD's. Then if you are paranoid, wipe the drive with something like KillDisk or DBAN. This will DESTROY any data on your drive. So make sure you get whatever you need off it. Then from the recovery DVD (or USB thumb drive) select "Minimal Recovery Installation". At least that option has been in every HP I've owned (3 to date). This will install the OS and all drivers and minimum required HP apps and recreate the recovery partition. It will be like new.