I have a shop built pc running windows 2000 pro and i think i have deleted some of the operating system files but i dont have any disks or anything is it possible to use somebody elses 200 disk to repair my system or do i have to go back to shop for a clean install and pay £30 because i know its my fault because i had trouble trying to install dvd burning software after buying a dvd writer which caused system to keep crashing also could it be a memory problem?