Windows 7 Device Manager Empty

The device manager on my Dell XPS running Win 7 is empty. I've also noted that the desktop can't find my wireless printer on the network resulting in I can't scan to the computer. The printer worked fine 2 weeks ago so believe the behavior started within the past 2 weeks. It also doesn't seem to be able to find some devices plugged into a usb port like a camera. It does find a flash drive and correctly reports it in my computer but nothing in device manager. I tried restore and did not have a restore point that would go back far enough to correct the problem. I've checked the enum settings in the registry and they are correct. I've performed sfc /scannow, no problems. I've performed CHKDSK -r and found no problems. I've seen many, many reports on the device manager being empty in both XP and Win 7 but none of the solutions have worked (edit the enum setting in the registry, run sfc /scannow, CHKDSK, etc. I realize I can just do a re-installation of Windows 7, but would like to avoid that if possible. Just wondering if anyone has other possible solutions. Thanks, Bobby