Device Manager shows a yellow exclamation mark if:

• the driver was not installed when prompted for
• there are duplicate devices on the system
• there are resource conflicts

A yellow question mark appears if the device cannot be identified by the OS. Use device Manager to check if all devices have been detected and configured, print summary of devices or to changfe configuration settings. General tab allows you to enable/disable a device. Device Manager runs read-only when focus switched to a remote machine.

Use Device Manager to update, rollback and uninstall drivers. Update option automatically backups replaced driver, allowing for rollback. Uninstalling a driver will uninstall a device only if the device was configured through PnP detection. If the driver was added manually, the device will remain in device manager, although there will be no driver for it. Most device resources are configured automatically and do not allow for manual configuration. When device resource are set manually, then these resources can not be used for automatic configuration, and could cause problems for other devices. Some devices provide their own control panel icons: use group policy to disable them.Users can install PnP drivers provided that the driver is already on the computer, it has a digital signature and the no further actions required than PnP detection. Thus users can connect and use many USB and IEEE 1394 devices, including printers. Use sysdm.cpl, Hardware, Driver Signing, to control how unsigned drivers are handled (ignore | warn | block). To prevent users from changing these settings use group policy:

• deny access to hardware properties pages in control panel
• disable mmc snap-in for device manager in compmgmt

Several techniques available to recover from problematic driver installations:

• driver rollback
• last known good 9only useful if you have been unable to login since install)
• safe mode
• recovery console (requires local administrator password or Directory Services Restore Mode password for DCs)