Hi Mama Taz,
I had a Compaq Presario 7477, and yes Compaq Bios info is crap, Compaq don't want the punters messing with it
It's the old story, unless hard drives have S.M.A.R.T. technology, hard drives appear to work fine right up untill they fail. I'm not saying it is your hard drive that is faulty, but the only PC component that has failed for me is hard drives. As the hard drive is the only component with mechanical moving parts it is understandable. I've had two hard drives fail on two seperate PC's and I've have had one replacement fail, plus one additional new hard drive fail.
So illiminating hard drive failure problems would be wise. I know Compaq have a hard drive diagnostics program that you can download onto a floppy disk. So I suggest you go on to a Compaq tech support forum or email Compaq tech support for the web link to the download. Once downloaded, reboot the faulty PC with the floppy disk, and follow the on screen instructions.