One problem sometimes encountered by Windows PC users is the sudden failure of the DVD and/or CD (or "optical") drive. Optical drives do fail in time (as the lasers fail), but sudden failures are often the result of an easily fixed problem in the Windows registry. One symptom of the failure is the disappearance of the optical drive (and its drive letter) altogether from the list of drives under "Computer" (Windows Vista and Windows 7) or "My Computer" (for Windows XP). Another symptom of the failure is evident in the Windows "Device Manager" (right-click "Computer"/"My Computer," > "Manage" > "Device Manager"). The drive(s) may appear, but are listed with a failed or missing driver. The problem of missing drives typically occurs after the installation of an application such as disk burning or photo editing software, or an MP3 manager. The key, here, is that the drive disappears suddenly. If this is your problem, a simple fix using the Registry Editor may be the solution.

Locating the DVD Key in the Registry

Here are the steps for fixing the problem in the Registry. They essentially involve deleting the "Lower Filters" and "Upper Filters" values:

1. Start the Windows registry editor by typing "regedit" in the search or Run window, and hit "Enter." (It would be beneficial to expand the window to full screen if it is not already expanded in order to see as much of the information as possible.)

2. In the left panel, navigate down the list (by double-clicking) to this location:

HKEY_LOCAL_MACHINE

SYSTEM

CurrentControlSet

Control

Class

{4D36E965-E325-11CE-BFC1-08002BE10318}

You should see a screen that looks very similar to the picture above. Make sure that you see "DVD/CD-ROM drives" under the Data column in the upper right corner.

3. Now, to protect yourself against failure with this method, right-click the folder in the left column that reads "{4D36E965-E325-11CE-BFC1-08002BE10318}." Click "Export" in the drop-down menu, give this file a name, and then save it in some location that you will remember (the desktop is a good place). Once you've backed up this key, you may safely delete entries without fear of corrupting the any Windows functionality.

4. Now, look for the entries in the right column that read "Lower Filters" and "Upper Filters." Single-click (to highlight in blue) each one of these values and then delete them (either by using the "delete" key or by right-clicking the mouse and choosing "delete" in the drop-down menu).

5. Once the values have been deleted, close the Registry and reboot your computer. Look to see if your optical drives have re-appeared in the list of drives, and test them by reading a disk. If they work, the fix was successful.

6. If this fix did not work, then the problem lies elsewhere and cannot be fixed by editing Registry keys. It is probably wise to restore the Registry to its prior condition, which can be simply done by double-clicking the saved Registry backup file from step #3. Other diagnostics will have to be performed to determine how to fix your optical drive problem.