Borrowed from SevenForums:
"I had this problem too upon installing windows 7 with a code 52 error.
to fix it:
- execute regedit
- search the key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E965-E325-11CE-BFC1-08002BE10318}
- When you found it delete Upperfilter and lowerfilter entries.
- Reboot your system.
You'll see your DVD-ROM drive in your computer again and
it will work."