mh ... that's strange. did you try vista, did it work there? is your drive recognized in your BIOS?
are you sure the device isn't just listed in the wrong category (unrecognized devices or something). it's really unlikely that your device get's recognized by your BIOS but not AT ALL by windows.
also try "view->show hidden devices" (don't know if it's really called that in the english version of windows, but I hope you'll find it
) in your device manager
but windows 7 seems to have major problems with dvd drives anyways.