When the device manager displays a yellow question mark next to a device name, it probably means that one of the hardware components is not installed correctly. If you installed a new component and failed to install the software for it as well, it simply won’t work. If you know which component you added, you can install the drivers from the CD or download the software from the manufacturer’s Web site. However, sometimes you have no idea which device has been marked because the device manager hasn’t identified it. All you can see in the list is ”unknown device”.

If you haven’t installed anything recently, then it’s possible that a system device is experiencing the problem. In this case, you have to download all Windows updates and install the latest service pack.

On the other hand, if you suspect which device needs to be installed but you don’t know how and where to find the drivers, you must use the Everest software. Everest Home Edition is a free hardware diagnostics and memory benchmarking solution for Home PC users. It offers accurate hardware information and diagnostics capabilities. With this program, you can identify all hardware components and find information about the manufacturers and even links to the latest drivers on the Internet. Unfortunately, the manufacturer has discontinued the production of the free version in 2005, but you can still find it here. Everest Ultimate and Corporate editions can be found at the Lavalys Web site.

Everest is especially handy when you need to find drivers for the motherboard, video cards and network adapters. When the installation is complete, just select Computer and then Summary. It will display all information about your hardware.

There are also some other programs that can identify hardware and show you the way to the drivers, such as Driver Max and Unknown Device Identifier. Read more here.