If you're trying to recover data from the hard drive, and Windows won't accle, then I'd suggest using a bootable CD with Knoppix. That will run from the CD and allow you to read stuff off the hard drive if it's at all readable. I've recovered important files for several friends that way. You then save to floppies or down the network if you have one.
If you just want to get the computer working again, and the data on it don't need to be recovered, then I'd remove the hard drive and fit a replacement (Ebay may be a suitable source). You could even fit a larger HD to give yourself more working space.