First i changed the motherboard ..then i noticed i need to reinstall windows 7 ... so i tired to reinstall my oem win 7 ...it wouldn't repair or load my old copy of win 7 ...so i order a new copy of win 7 and a new hard drive . So my question is how hard is it to reinstall win 7 on my old hdd and can i delete all the old crap on it ? ...or should i throw away my old hdd and do a fresh install on my new one? plus i really like to keep both of them can if i can delete the crap off the old hdd. thanks in advance for the help.