1. Make sure both the power and data connections to the DVD-RW are still properly seated.
2. Follow these procedures to remove the Upper and Lower registry filters for the optical drive, this is a very common problem, especially when new software that interacts with optical drive is installed. Do not delete anything else other than what is specifically mentioned, otherwise you may cause system instability issues as removing keys from the registry is risky if you are unsure of what you are doing.
1) Close all open programs
2) Click on Start, Run, and type REGEDIT and press Enter
2.a) Make a backup of your registry by going to the File menu and using the backup option, just save the copy to your Desktop or removable drive (if available) until you are finished
3) Click on the plus signs (+) next to the following folders
4) This folder is the DVD/CD-ROM Drive Class Description in the registry. Look for any of the following names in the right hand column.
5) If any of the above keys shown in step 4 are listed, right-click on them and choose Delete
6) After deleting the keys, close the Registry Editor
7) Reboot your computer
8) Open My Computer and check to see if your CD or DVD drives have returned. You may also want to open Device Manager and verify that the yellow exclamation and error code on the CD or DVD drive is gone