Device Manager displays only non-Plug and Play devices, drivers, and printers when you click Show hidden devices on the View menu. Devices that you install that are not connected to the computer (such as a Universal Serial Bus [USB] device or "ghosted" devices) are not displayed in Device Manager, even when you click Show hidden devices.
At a command prompt, type the following command , and then press ENTER:
set devmgr_show_nonpresent_devices=1
Then click Show hidden devices on the View menu in Device Manager before you can see devices that are not connected to the computer