O boy. A power supply would would B a good start.It could b a HDD pblm also,   you have to start some wareSince the HDD worked fine in my computer I have ordered a new 500w Antec power supply from Newegg.  We'll see where to go from there.  If nothing else, I can USE the power supply to rule out parts in the future.OK. Hope the new power supply is all that is necessary?Be carfull when dis. connecting & re installingTry a HDD diognostic utitity from your HDD manufacturers website to check the hard disk health?No No No.... I think I have the answer since this happened to me alot, what happens is windows would have to reinstalled when this happened to me or disconnect an reconnect the cable's.  Tell me what drive is it maxtor,western???  How did you format set it up?  If its maxtor you cant use any old versions.  You need an have to use maxblast 5.    Which was my problem.Squall... thanks for your input.  The HD is a Western and is a bit old, but I think it is holding up.  I tried ANOTHER working HD in that computer but I had the same those variables through other tests.  I really BELIEVE that the problem is the power supply or the MOBO.  If it is the HD, that's an easy fix as I already have all necessary info backed up.  I'll keep you posted, and thanks for the help.As opposed to just buying a PSU borrow a known good one from someone overnight  to see if it is in fact the issue...
As to the drive DLoad and run WD's Data Lifeguard Tools to check the drive...Free from their site.
Run the long Test...before going to bed for the evening.Like I said it was my problem.  Mite have tied into yours, it took me about a year till I got it tooken to a repair shop to find that out, hopefully it wont be to hard of a fix.  this ever get fixed?Hey Squall... Sorry I didn't get to post back... I have been out of town for a bit.  I got important FILES off the computer, reformatted the hard drive, and reinstalled Windows XP.  It runs like a charm.  Thank you for all of your helpYou KNOW where we are if trouble occurs again.