There is a weird registry issue which can cause CD/DVD drives to not work, to go yellow-questionmark in the device manager. According to many resources, it exists under both XP and Vista. However, the Microsoft web site standard fix does not always work. Here are steps:

1. Search the registry for the word “UpperFilters”.
2. There are likely to be several matches. Only some of them have to do with CD-ROMs. This will be obvious by context. When you see such a one, delete the “UpperFilters” key only.
3. Do the same for “LowerFilters”.

Sometimes, this happens because registry folders have had permissions changed by antivirus or other software. If the key cannot be deleted, this is the problem. You will need to right-click on the folder and add permissions, and then do the deletion. It is usually most straightforward to add the permission to the user logged in, though you’ll have to play with the dialog box if you’re on a domain.