With this tweak you can show all hidden devices in the device manager.

To do this, follow the next steps:

1. Open the Registry Editor click on the Start button on your taskbar, then click on Run and type "regedit" and click on OK to start the regedit utility.
    
2. Expand HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Environment (see picture 1).
   
   

   Picture 1

3. Create a new STRING value, or modify the existing value, called "DEVMGR_SHOW_NONPRESENT_DEVICES" and set it according to the value data above.
    
4. The modifications you made will be in effect after you reboot your PC.