Why does Device Manager show an Exclamation Mark for My CD/DVD drive?

1. To fix the problem on Windows XP, go to the Start Menu, click Run, then type Regedit and press Enter.

2. The registry editor will now open. Expand the HKey_Local_Machine then click on the System directory. Expand the System folder, followed by the CurrentControlSet sub-directory.

3. Click on the Control key, then expand the Class key: under the class key locate and select the following string - 4D36E965-E325-11CE-BFC1-08002BE10318. On the right hand side select LowerFilters and UpperFilters and hit the Delete key.

4. After deleting these keys, reboot the computer. This should make the exclamation mark go away, and the CD-ROM should start working again.

Note: deleting the whole 4D36E965-E325-11CE-BFC1-08002BE10318 key should resolve the issue as well, and after rebooting the computer the string will be recreated. Try deleting only the lower and upper filters first, and if that does not work, delete the entire 4D36E965-E325-11CE-BFC1-08002BE10318 key.