What to do if you open up your device manager & its empty ! Blank !
Here's how you do it:
Click on Start, then Run, and type in REGEDT32.
Click on the HKEY_LOCAL_MACHINE window or expand that hive and navigate to the following key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum
Now right-click on Enum and choose Permissions.
If the Group or user names list box is empty, then you know this is the problem!
It should have two names in there, System and Everyone.
Click the Add button and type in Everyone and click OK. Check the Allow box next to Read for Everyone. Now click Add again and type in System. Check the Allow box next to Read and Full Control for System. It should look like this:
Both the check boxes under Allow should be selected when you highlight System.
Also be sure to click on the Advanced button after adding both users and selecting Reset permission entries on all child objects with entries shown here that apply to child objects.
Click OK and if a warning message comes up, just click OK.
Close the Registry Editor and restart your computer.
You should now be able to see everything in the Device Manager.