Mental_Myopia

Perhaps the drives' jumper settings are incorrect. Check out the documentation for the hard drive.

Another possibility are some errors on the disk, especially in the boot sector. Check the brand of hard drive and go to their site. I know that Maxtor and Western Digital have free downloads that will make a bootable floppy that will check your disk for errors and tell you what's wrong.

Boot disks won't wipe hard drives. Formatting a hard drive wipes it out, though. A boot disk is simply to get to Windows or DOS in case something goes bad with the hard drive.

If you're unable to boot the hard drive, you may very likely be able to rescue your files by hooking that drive up as a slave in another computer, so don't worry. Just remember to set the jumpers and connections correctly in the other computer.