Ezek a lépések kellenek ha valaki nem találkozott volna még vele (fontos, hogy a 2-3 lépés között NE zárjuk be a cmd ablakot):
https://support.microsoft.com/en-us/kb/315539
To work around this behavior and display devices when you click Show hidden devices:
1. Click Start, point to All Programs, point to Accessories, and then click Command Prompt.
2. At a command prompt, type the following command , and then press ENTER:
set devmgr_show_nonpresent_devices=1
3.Type the following command a command prompt, and then press ENTER:
start devmgmt.msc
4. Click Show hidden devices on the View menu in Device Manager before you can see devices that are not connected to the computer.
5. Troubleshoot the devices and drivers in Device Manager.
When you finish troubleshooting, close Device Manager.
Type exit at the command prompt.
Note that when you close the command prompt window, Window clears the devmgr_show_nonpresent_devices=1 variable that you set in step 2 and prevents ghosted devices from being displayed when you click Show hidden devices.