[Achilles]

Dell (often) have their own inhouse staff alter the bioses of the motherboards they ship most frequently ie. family and low-end machines. 99.9% of motherboards are able to detect how many and what type of device is connected to each ide Channel. Assuming the cd-rom and harddrives are ide.

The easiest way to determine if it is the bios that's the problem would be to update with the latest one from the actual manufacturer.

Of course it could just be that the cd drive died with unfortunately coincidental timing. Try it in another machine. Try another one in the troubled machine.

Also, in fairness to Dell, while their machines are put together terribly, they are far from the worst out there.