You have an common issue that your CD/DVD drive isn’t accessible/viewable via the Windows Explorer and that your CD/DVD device is marked with an yellow exclamation mark in the Device manager, saying Windows couldn’t load the drivers for that device?
You search for it and find some ‘strange’ registry sub key with the value 4D36E965-E325-11CE-BFC1-08002BE10318 (HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Class) and the advice to delete the UpperFilters or LowerFilters keys.
After a reboot your system works again, especially your CD/DVD…
Now you think, what it is all about or can that happen again?
First, here is a picture which explains the types of a Windows Driver Model Driver:
More information are here.
A deeper look into the Upper- and Lowerfilters in Windows and how to check/fix issues visit this site:
More CD/DVD Problems issues and how to fix them are here.