If you're comfortable opening up your computer's case, I would suggest first checking to make sure both the IDE cable (The big flat one) and the power cable are still connected. You should also check that the other end of the IDE is connected to the motherboard. Either of these 2 cables coming disconnected could cause the problems you are talking about.
Second, I would try just jiggling (complicated techical term, eh?) the above mentioned wires (while the computer is off, of course) and then rebooting. Hey, you might get lucky.
Third, I would physically detach both cables, then restart the computer. Then, shut down the computer, reattach both cables, and turn the computer back on again. If it is a driver/software issue, this should cause Windows to think the drive is new hardware and install it for you.
If none of the above work, you might have to buy a new CDROM. Make sure you buy it from a store that will give you cash if you return it. Why would you return it? If the new drive doesn't work, either, than the problem is most likely with the motherboard. You may as well get your money back for the CDROM, as you will need it when you buy a new PC.
Good luck!