help, i tried to run an old pc (well, not that old AMD 64 athlon) I CLEANED it (inside and out) and when I turn it on, it says "using partition 0, partition 3 loading err r" and it will not BOOT in OS... can anybody have an idea? I don't know what the OS INSTALLED in the HD...Guessing this computer was saved from someone else throwing it away? I'd start with booting it off of a Live Linux CD such as Knoppix or even use Ubuntu. Boot off of the CD and then use the utilities contained within this Linux OS to diagnose further to try to get the original OS back up and running. Otherwise if you can locate a key label on the outside of the computer which is a Microsoft Key Label you will have a good idea of what Operating SYSTEM came with the system originally and then be able to acquire a OEM copy of the matching OS on disc and then install clean (maybe) to the hard drive if the hard drive is not crashed beyond repair. Then if it installs successfully you can use the key on the computer itself to activate against windows if Windows XP or newer and have a good working computer maybe.ok THANKS i will try..