A friend of mine asked me to work on his PC that had this same problem. All of a sudden one day Windows no longer recognized his CD Rom drive. The bios reocginized the drive, but Windows did not. I did a search on the web and found the following advise and it worked for me !!
If your CD/DVD Drives won't appear in your list of drives, you can probably correct this as follows:
Open regedit. Navigate to
Export the key for backup. Delete any value named "UpperFilters" or "LowerFilters" (Only exact match!). Repeat for every ControlSet???. Reboot.
Explanation: Drivers for devices are modularized. It wouldn't make sense for them not to be, as, for example, filesystem drivers would have to know how to talk to every possible type of hard drive. Part of this modularization is called the device stack. The IO Manager interfaces with the top driver on the stack, and the bottom driver on the stack interfaces with the physical hardware.
The keys under the Class key each specify a hardware type. When hardware of that type is installed, the device-specific driver for the given device type is loaded and used. To modify that drivers behavior, a second driver--called a filter driver--can specify that it wishes to be above or below the device-specific driver. The UpperFilters and LowerFilters keys specify the name(s) of the filter driver(s). Some programs that install filter drivers are: Packet-writing support, such as InCD; iTunes.
If one of the drivers referenced in these keys cannot be found (under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es),
loading the driver for the device fails.
Alternatively, you can try this fix from the Doug Knox site:
Restore CD/DVD Drives to Explorer