The DVD/CD-ROM drive is not able to be seen in windows explorer

The DVD/CD-ROM drive is not able to be seen in windows explorer. In the device manager, the DVD/CD-ROM drives appear with exclamation mark.
(Note : for back up Import all registry on ur deskptop )
   1. On the Windows Start menu, click Run.
   2. In the Open box, type Regedit and click OK.
   3. Select the following key in the Windows registry:
   4. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\
      {4D36E965-E325-11CE-BFC1-08002BE10318}
   5. On the Edit menu, click Delete:
      Value Name: LowerFilters
      Value Name: UpperFilters
   6. On the Registry menu, click Exit.
   7. Reboot your computer.

Sometimes, you may find only one of the Value Name. You can continue to delete it and restart your computer.