Sounds like a boot sector virus, do the following.
1. Google "Delpart" and download it.
2. Obtain a copy of FDISK
3. Create a boot disk and load Delpart and Fdisk on it.
4. Boot the machine from the floppy.
5. Run Delpart and delete the partition.
6. Execute the following command "FDISK /MBR" 6 times in quick succession this should kill the most persistent boot sector virus.

The fact that the W/S doesn't recognize any other drive may only mean that the BIOS isn't set to auto detect.

>I have a relative's computer that I have been trying to rebuild for a couple weeks now. I can go get the specific model and all that if needed, but basically it is an 6-year old Compaq. They got a very bad virus that I was unable to remove. So I backed up their data and thought I would just wipe the hard drive and reinstall the OS. The wiping part went just fine, but I was unable to finish as the install itself would freeze up, regardless of which XP Pro disks I used. Well, I figured that was ok as I had some extra hard drives kicking around, but when I hooked them up and tried to install the OS, a message would popup saying that I could not do that because I was trying to install a different OS than the original and the hard drive would not be recognized. It was almost like the computer would only recognize the original drive, but none of my OS would install to that drive. I hate to give up on it as they really can't afford a new box, but I'm not sure what else to try. I have already put about 10 hours into this and I just can't seem to get it to work. Any ideas?