NWA-PCUG Newsletter Article, July 2009
Eliminating Obsolete Windows Device Drivers
By Vinny La Bash, Regular Contributor,
Sarasota Personal Computer Users Group, Inc., Florida

http://www.spcug.org
vlabash (at) comcast.net (click to email author)

This article has been obtained from APCUG with the authorís permission for publication by APCUG member groups; all other uses require the permission of the author (see e-mail address above).

Device drivers are programs that are designed to control (drive) specific types of hardware (devices) that are attached to your computer. These devices can be attached through wires or by wireless connections. No matter how the device is attached you need a program to tell it how to interact with the computer. An operating system such as Windows comes with myriads of device drivers built into it so when you bring your new computer home, attach your printers, external drives, etc., most of them work fine.

The caveat is that drivers are hardware dependent and operating system specific so your external CD-ROM, which worked flawlessly under Vista, may not work with Windows 7 until you install an updated device driver designed for the new OS.

Every operating system directs device drivers to communicate with their devices through the computer bus or a communications subsystem. It is a process which is largely invisible to those trying to get work done on the computer, much like the internal workings of an automobile are largely invisible to a driver trying to get from home to the grocery store.

The invisibility of device drivers is a good thing when everything is working smoothly, but it tends to hinder troubleshooting when trying to track down the cause of a problem. When you upgrade or change hardware, Windows doesnít usually delete the old device drivers. Sometimes these obsolete programs can cause hardware conflicts. Seemingly unrelated quirky behavior on the part of the computer can often be traced to a no longer used device driver.

Resolving device driver problems in Windows can be difficult. In this article weíre going to focus on finding outdated device drivers and eliminating them from your system.

Manually searching for device drivers on a Windows system can be frustrating, time-consuming, and mostly a waste of effort. Conveniently for us, Microsoft has provided a way to locate unused device drivers and remove them.

The directions herein are designed specifically for Windows 7, but the general process will work for Vista and XP. There are slight variations in the process with each of the operating systems; just be careful when reading each screen. Letís get on with it.

The Device Manager as it comes from Microsoft is not set up to display device drivers that are no longer being used. The Device Manager has to be configured to show obsolete drivers so we can remove them. You need to add something called a special Windows Environment Variable. This is a text string that contains a path, file name or drive. Programmers refer to this as a system property. We donít really care what they call it as long as it works.

1. From the Start Menu, right-click on Computer.
2. Select Properties at the bottom of the list.
3. From the System window, select Advanced system settings.
4. From the System Properties dialog box, select the Environment Variables button. (See illustration)
5. The Environment Variables dialog box contains two panels, User variables and System variables.
6. Click the NewÖ button.
7. In the New System Variable dialog box, type devmgr_show_nonpresent_devices
8. Type 1 in the Variable Value text box.
9. Close all the dialog boxes.

In most cases there is no need to restart the system. Letís test the results of our labor.

1. Access the Start Menu.
2. Right click Computer.
3. Select Manage.
4. When the Computer Management window appears, select Device Manager.
5. Open the View menu and select Show Hidden Devices.

From now on whenever you open a branch within the Device Manager tree structure and device icons are "grayed out" or appear faded, these are the unused drivers. You can safely delete them. Whenever you add, remove or change your hardware configuration, always check for left over drivers and avoid problems.

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