How to remove stale driver devices in Windows 7

Some people don't care about the old drive devices in Windows 7, but if you find that some recently installed devices are not working properly or often cause the computer to crash, then you can consider deleting the old or unused Windows 7 Device driver.
1. Right click on the Win7 desktop & ldquo; Computer & rdquo;, select “ Properties & rdquo;.
2, found in the left panel "advanced system settings", click on the "advanced" tab at the bottom of the "environment variable".
3, in the upper part of the "XX user variable", click "ld"; New & rdquo;
Enter the variable name: devmgr_show_nonpresent_devices
Input variable value: 1, and finally click & ldquo; OK & rdquo ; button.
4, right click on the desktop "computer", select "ldquo; management", open the "Device Manager" on the left side.
5, in the top menu bar of the device manager, select “ view & rdquo; & mdash; & mdash; & ldquo; show hidden devices & rdquo;.
6, so you can find "Other devices" on the right side of the device manager.
7, right-click not to use "unknown device", uninstall it!