Chances are you have a SCSI controller or an IDE RAID controller either built-in to your motherboard or in your PC.
One way to find out is to open your PC and look to see if you have a SCSI controller or if your motherboard has a built-in RAID controller (should have a little chip that says something starting with "HPT"). If you do have a built-in HPT RAID controller, you need the diskette that comes with your motherboard. It will contain the necessary driver. If you can't find this diskette, go to www.drivershq.com and search for an HPT driver. Make sure you're looking for the driver for the right chipset (there should be something about this on a chip on your motherboard).