Typically, unless somehow very unique, optical drives do not require third party drivers in order to be seen by and used by Windows 7.
Have you had an opportunity to open the case and inspect the interface and power cables to confirm that they are seated properly (both ends of interface cable)?
Have you recently installed any new motherboard drivers (chipset, disk controller or BIOS update)?
Are the drives identified and listed during POST? If you enter the System BIOS utility are the drives being seen?
Are you using any third party software (TweakUI / PowerToys) to hide the drives?
Have you tried this Your CD drive or DVD drive is missing or is not recognized by Windows or other programs