Device Manager Empty

My device manager is empty and I am unable to use certain USB devices such as a webcam and digital camera. I tried system restore back a week; no matter what date I picked, it was unable to restore. I checked for the apropos virus; not infected.

 

Check HERE for a possible solution.

Also be sure you have the Plug and Play service set to Automatic and verify that it is running.

 

The problem was in the security settings not in Plug n Play or any of a long list of other problems that can cause this like particularly nasty viruses.

This is what I did after backing up my registry:
Ran Regedit.
Scrolled to HKEY_LOCAL_Machine and then to System\CurrentControlSet\Enum. I right clicked on Enum and clicked on Permissions.

I was missing the settings of Everyone and System. I added them both using the add button. To set the required permissions, Everyone was set to Read under allow; Systems was set to Full Control (which also checked Read).

I clicked on the advance button and on the Permissions Tab checked Replace permission entries on all child objects with....." and clicked OK and Yes. Then I closed the Registry Editor, rebooted, and found my device manager.