One of my technicians was having a problem with a CD-ROM drive. Any optical drive he attached would not work in Windows, and the Device Manager gave an error like “Error 31: Cannot load the drivers for this device.”
I had seen the problem before and knew it was related to UpperFilters and LowerFilters in the registry, but I, in a stupid moment, couldn’t remember that detail, so I couldn’t find the registry entry.
My technician, however, was really smart and was able to find a fix for the problem on his own, about an hour later. The moment he said UpperFilters, the fix came rushing back into my brain.
Beware of the Upper and LowerFilters issue. Some CD/DVD writer software and even some malware plug themselves in there, and can cause you headaches if the filter driver file becomes lost or corrupt.