how to show hidden device?

Sometimes we want to disable the unused devices to better the performance of our computer. But, the problem that we have is, sometimes, these devices are hidden by Windows. To solve this problem, we have the following two methods. One is to show hidden devices temporarily and the other is to show it permanently. The following is what we need to do.
1. To view hidden devices temporarily.

1) Right-click My Computers

2) Click Properties

3) Click Device Manager.

4) On the View menu, click Show hidden devices.

5) All hidden devices are displayed.

2. To view hidden devices permanently.

1) Click Start and click Run.

2) Type "regedit"

3) Go to

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Session Manager\Environment

4) Add a string "DEVMGR_SHOW_NONPRESENT_DEVICESP"

5) Type a value of 1.