Go into bios and see if it is in there somewhere. (does it have power?)
If it isn't, open up the case and make sure the cable and power is connected securely.
Check bios again, and windows, if still no luck:
Check the back of the CD rom for a little 2 pin thing in the back. Move that to slave or master or slave2/master2, fiddle with that and keep rebooting bios/windows for awhile after you've tried the combinations.
If still no luck... Try to put the IDE cable into a different socket on the motherboard. Or connect it to the same cable as the harddrive.
Recycle through slave/master pins
Make sure you check bios as it'll be likely it will detect it first 99% of the time and it'll save you from rebooting to windows everytime.
If you have tried every pin, every cable, and gone through bios, then the rom is probably broke.
Without being there to see what the rest of your equipment is set to and without more information, thats as simple as I can put it. Doing these tests will not hurt anything as long as you're careful not to rip something apart.