The best thing really to do is go to the drive manufacturer's website, and find and download their diagnostic software for your hard drive. Unfortunately, you'll need some kind of DOS-bootable floppy or hard drive partition to RUN the software. I just had two hard drives go to a series of brownouts, and ran the (Western Digital's and Maxtor's) software to test the drives that hadn't yet gone bad. I found out that neither company's software will work correctly under FreeDOS (as of last week's beta release) due to something with the way the programs handle the console.
So you might need to use a licensed version of some company's DOS to run the software. -- Ferret no baka