Device drivers are essential to the proper operation of Windows Server 2003. A faulty device driver can cause many problems on your systems—everything from unexpected restarts to application hangs to blue screens. To make it easier to detect and diagnose problems, you should maintain an inventory of all installed device drivers on systems you manage. Previously, we talked about using the DRIVERQUERY command to obtain a list of drivers for computers throughout the network. Ideally, the driver information should be stored on a centralized network share rather than on individual computers or could be printed out and placed in a binder where it is easily accessible. You should then periodically check manufacturer Web sites for known problems with related device drivers and for updated drivers. Windows Update can also help you because driver updates are made available through this service and can be installed automatically.

Although you can be fairly certain drivers obtained through Windows Update are newer than installed versions, this isn't the case for drivers you download yourself, and you should always double-check the driver version information before installation. As discussed previously, the current driver version is displayed in the driver's Properties dialog box, as shown in the following screen. Double-click the device in Device Manager to display the driver's Properties dialog box, then select the Driver tab. Be sure to check the driver date as well as the driver version.

Next, check the driver version information for the driver you downloaded. To do this, unzip the downloaded driver files to a folder. In the folder, you should find .dll or .sys files. Rightclick one of these files, and choose Properties. Then in the Properties dialog box, choose the Version tab to find the version information.

To continue with the installation of downloaded drivers, check to see whether the driver download includes a Setup program. If it does, run this program so that the proper files are copied to your system. Once you do this, you can use the Hardware Update Wizard to install the driver. This wizard is started by accessing the driver's Properties dialog box through Device Manager and then clicking the Update Driver button in the Driver tab. As you'll see, the Hardware Update Wizard is essentially the same as the Add Hardware Wizard (see the following screen). Because of this, you follow the same procedures as discussed in the section entitled "Setting Up New Hardware Devices" earlier in this chapter. Keep in mind that in some cases you must reboot the system to activate the updated device driver.

Occasionally, you'll find that an updated driver doesn't work as expected. It could cause problems, such as device failure or system instability. In most cases, this should occur only when you've installed unsigned device drivers as a last resort or beta versions of new drivers that might have improved performance or some other benefit that outweighs their potential to crash the system. However, it can sometimes occur with signed device drivers—even those published through Windows Update.

If you suspect that an updated driver is causing the system or device problems you are experiencing, you can attempt to recover the system to the previously installed device driver. Double-click the device in Device Manager to display the driver's Properties dialog box. Then in the Driver tab, click Rollback Driver.

Windows device drivers for Plug and Play devices are loaded and unloaded dynamically. You can remove the driver for a device only when the device is plugged in. This means the proper way to remove a device from a system is first to uninstall its related device driver and then to remove the device from the system.

One reason for uninstalling a device is to remove a device that is no longer used or needed. Start by uninstalling the related device driver. Double-click the device in Device Manager to display the driver's Properties dialog box. Then in the Driver tab, click Uninstall. When prompted, click OK to confirm that you want to remove the driver. Windows Server 2003 will then remove the related files and Registry settings.

At this point, you can shut down the system and remove the related hardware component if you want to. However, you might first want to check to see how the computer operates without the device in case some unforeseen problem or error occurs. So, rather than removing the device, you'll want to disable it. Disabling the device prevents Windows from reinstalling the device automatically the next time you restart the system. You disable a device by rightclicking it in Device Manager and then selecting Disable.

Sometimes when you are troubleshooting and trying to get a device to work properly, you might want to uninstall to unplug the device temporarily. Here, you could disable the device and then monitor the system to see whether problems previously experienced reoccur, or you could reinstall the device to see whether normal operations are restored. Uninstalling and then reinstalling the device forces Windows to go back to the device's original device and Registry settings, which can sometimes recover the device.

After you've uninstalled a device driver, one way to get Windows Server 2003 to reinstall the device is to reboot the computer. You can also try to rescan for devices using Device Manager by choosing Scan For Hardware Changes on the Action menu. Either way, the operating system should detect the uninstalled device as new hardware and then automatically reinstall the necessary device driver. If this doesn't happen, you must reinstall the device manually using the Add Hardware Wizard as discussed earlier in this chapter.