1. Try setting the Hard Drive in CS (Cable Select) if it now is in MA (Master) or vice versa.
2. Try another Hard Drive
3. Replace the IDE HD Cable... if the cable is 40 strands, replace it for a 80 strand cable before anything
4. Move the Hard Drive to the Secondary IDE Channel
5. Reset the BIOS with the battery removed for 5 to 10 minutes
6. Disable the BIOS S.M.A.R.T setting.
If the problem still persists, the motherboard has probably failed.