This problem came to me as well as many other users of windows 7 when we upgraded or made a clean install to/of windows 8. Windows 8 didn't list 1 dvd drive thus into the "My computer" window it was just listed the one of the 2 DvD drives.
To fix that problem you can try this:
1.Open a command line window with admin rights (win key + X then select command line (admin))
2.Then type or paste that into CMD and reboot.
reg.exe add "HKLM\System\CurrentControlSet\Services\atapi\Controller0" /f /v EnumDevice1 /t REG_DWORD /d 0x00000001
P.S. Worked for me fine.