Is this the motherboard you're talking about?
ASUS P5GD1-VM Socket T (LGA 775) Intel 915G Micro ATX Intel Motherboard - Retail
If so, it has 2 IDE controllers. I think you should have the 2 hard drives on seperate channels (Primary and Seondary Masters) and put one of the CD Rom as the secondary slave. These days, having 2 optical drives is overkill. Most of the time, CD copies use the hard drive anyways for temp storage and buffer before it goes onto a blank disc.