I've googled this issue and apparently there are many others experiencing this issue in Windows 7. After a couple of hours or so, the Devices and Printers stage stops working. I see the green loading bar near the top SLOWLY move from the left to the right, but nothing happens andnone of the devices show. Restarting my computer fixes the issue for a short while, then it happens againafter alittle time. I've seen some posts suggest that it has something to do with bluetooth devices, but my computer does not have bluetooth or any bluetooth devices.

I have exactly the same problem, but i think it's my web cam is not compatible or something. I've installed a webcam Vista drivers, may be this is the problem.