BIOS older than May 1999 usually do not recognize drives over 32GB. Solutions:
1) use BIOS Pather (at your own risk, however, i my opinion it works good) - it will patch current BIOS to recognize drives up to 137GB,
or
2) find BIOS on manufacturer's site and flash (manufacturer and model can be found on board, usually between PCI slots, manufacturer can be recognized from lower BIOS string on first boot screen),
or
3) install IDE controller.