What to do if the DVD drive is no longer available in Explorer?

Check device manager, it might be that there is an error on the device. If there is an error with Code 19, you’ll have to change the following:

open regedit
navigate to
HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Control \ Class \ {4D36E965-E325-11CE-BFC1-08002BE10318}
there you’ll find “LowerFilters” and/or “UpperFilters”
delete these two keys and reboot the system

The DVD drive will be recognized as a new device and can be installed again. It will work properly after that re-installation.