The BIOS recognizes the CD drive. But windows 7 does not recognize it. It is also not appearing in the Device manager. I also tried the registry keys but the lower filter and upper filter are not appearing.
Click on the start pearl, in the search box type: Disk man.
select create and format hard disk partitions.
Once the winodow opens you should see a list of drives connected to the Pc
IE: C: system windows 7 OS . If you can see the dvd drive in the list, right click on it, click on: Change drive letter and paths, change the letter to one that is not used by another device or Hard disk drive.