My dvd drive is missing how do i get it back i

1. Start > Run.
2. regedit
3. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\Class in the Registry Editor dialog box and select the {4D36E965-E325-11CE-BFC1-08002BE10318} key, which appears as a folder.
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.