I got this computer from my old boss, i ve added some new hard drives,dvd cd drives, the computer turns on but says there is a file damaged or missing.it wont boot up. i went to the download center to get the manual, but there isnt one.its an intel corp manufactured unit. product # is d915gav, version aac64134-600,serial number laav60112100. any help with this system would be nice. thank you.