By default, Device Manager displays information about all currently installed and connected Plug and Play devices. To view devices that use non-Plug and Play drivers, as well as previ¬ously installed devices that are not currently connected, you need to tweak Device Manager.
- To view non-Plug and Play devices, open Device Manager and choose Show Hidden Devices from the View menu. In the default Devices By Type view, the formerly hid¬den devices will appear under the Non-Plug And Play Drivers branch.
- To view devices that were once installed but are no longer attached to the computer, open a Command Prompt window using the Run As Administrator option and enter the command:
Then, from the same command prompt, type devmgmt.msc to open Device Manager. Choose View, Show Hidden Devices. The new instance of Device Manager will show “ghosted” entries for devices that were once present. This technique is especially useful for fixing problems caused by leftover drivers after replacing a network card or video card—you can easily delete the ghosted device.
- To see advanced details about a device, open the properties dialog box for the device and look on the Details tab. The value shown under Device Instance Id is especially useful for tracking down devices that are detected incorrectly. The full details for a device ID shown here can be found in the registry, under HKLM\System\Current-ControlSet\Enum. Although we don’t recommend idly deleting found keys, this information might provide enough information to figure out why a device isn’t being identified properly.
Setting the DEVMGR environment variable as described here affects only the instance of Device Manager launched from that Command Prompt window. If you want the change to be persistent, open Control Panel, open System, click Advanced System Settings, click Environment Variables on the Advanced tab, and define a new variable for this setting. If you add the variable to the User Variables section, the setting will apply only to the current user. If you edit the System Variables section, the extra information will be visible in Device Man¬ager for all users of the current computer.