Problem

This problem is usually caused by the Sonic Record Now software. It adds a couple of registry entries that cause the CD / DVD drive(s) to disappear from explorer.

Resolution

You need to remove the upper and lower filters of your cd reg key.
1. Start > Run.
2. regedit
3. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class  and select {4D36E965-E325-11CE-BFC1-08002BE10318)
4. Select File > Export
5. save the file to the Desktop in case you need to restore it
6. In the right panel of the Registry Editor, select the LowerFilters line, and then choose Edit > Delete. Click Yes in the Confirm Key Delete dialog box.
7. Do the same for the UpperFilters line
8. Close the Registry Editor.
9. Restart Windows.