This has happened to me a couple of times over the years, usually because I did something stuped. I found 2 ways to take care of it. One to get the hdd mfg software for setting up the drive and boot it from the Floppy and format the drive. Of course you'll lose everything. The last time this happened I put in a new hdd and installed the OS. Then put the screwed one in as a 2hd hard drive, be sure to set up the BIOS to start from the Drive with the OS. I was able to copy all my files from old drive and then formatted the old one and am using it for storage.