whest said:
Try the solution on the following link - Your CD drive or DVD drive is missing or is not recognized by Windows or other programs
I just had a problem where after booting my PC and found my DVD no longer read DVD or CD discs. Scared the bejeebees out of me, because it would write CDs but then tell me that there was no legitimate media in the drive when I tried to read them back. (The scare is I don't want to have some store chain technician touching my PC for warranty support.)

I ran the Windows diagnostic that you linked in your post. It too, told me there was no legitimate media inserted.

None of my previously works discs were readable.

I disabled the device, rebooted, renabled it, and all seems well again.

I still don't know the cause, but I remember using this trick back in the days of printer support with older versions of Windows.

Just an FYI for the next person trying to resolve that Windows 7 no longer reads CD or DVD discs.