Bios not find drives

I have two HP xw8000 workstation that have identical setups. I had both working a week ago and I decided to reinstall xp. One of my system floopy drive has bad pins on the motherboard so the only way to reinstall the OS is to remove the drive, place them into the system with the working floopy. I have done this process before with success. Unfortunatally, this time I got the OS loaded on, but as I moved the drives to the original system the bios didn't recognize any drives. Not only that but when I tried to replace the original drives back in the floopy working workstation the same thing happened on that system. So, I am out 2 workstations. I am installing XP Pro. If anyone has some good advice. It would be very much appreciated. I know there are some smart people on this forum, I have read a lot of it so far trying to figure this problem out.