That is weird.
You could try resetting the bios, but it's different for all motherboards. If you want the DVD drive, connect this up as a Master.
Choose 1 or 2:
1. If theres no CMOS Memory Clearing Header (a switch close to the battery)
Remove the circular battery on the motherboard and leave it out for an hour or so and place it back (in the right polarity)
2. If there is a CMOS Memory Jumper
and if theres a switch near the battery (On some ABIT motherboards there is called the CMOS Memory Clearing Header to clear the memory from the BIOS)
and there should be a jumper set to 3 for normal operation. Take this out and place it in 1 to clear the memory and leave it in there for a few minutes then put it back to one.
3. Reboot computer, try again
Hope this helps