The first thing to do is check all cable connections. You may have shook the cable loose enough for it to not be seen in windows.
You don't say what your system is but if it's XP have you looked in event viewer to see if there are any problems?
Have you recently installed ay software? Roxio burning software and Norton's go-back have been known to cause this problem.
If the drive shows up on your bios try this.
Sometimes simply deleting the filter entries, from the registry, for the third-party device drivers fixes the problem. These entries can sometimes become damaged (which is what produces the "corrupt registry" warning).
To delete the offending keys, open the Registry and navigate to HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlClass\{4D36E965-E325-11CE-BFC1-08002BE10318}. . Delete the keys named UpperFilters and LowerFilters and reboot.
Be very careful in the registry as a wrong move or deletion can cause windows to be unbootable. I would backup the registry before doing anything.
Backing up and restoring the registry
http://support.microsoft.com/kb/322756If none of the above has worked you may have a dead drive. Check the drive in another computer to see if it works. Or try a different cdrom drive in your computer to see if windows will see it.
SRX660