It could be a faulty hard drive. Test it with a bootable CD containing the drive manufacturer's diagnostic software for DOS. The downloads will usually be in the form an ISO CD Image File. Links are here: http://www.tacktech.com/display.cfm?ttid=287
Create a CD from the ISO file with IMGBurn on any working computer: http://www.filehippo.com/download_imgburn
Boot your faulty computer from that CD and test the hard drive.
Note: When posting on a forum you should not type every word in capitals as it's considered as "shouting" which is impolite, it also makes the post harder to read when there is more than one sentence.
It's worth remembering that many forum helpers will just ignore a post where all words are capital letters.