You've probably had a time when you got a new piece of hardware and hooked it up to your system only to find out that you can't get it to work. Sometimes, especially with USB devices, if you don't install the drivers when Windows first detects the new device, you end up spending hours trying to get the new device working.
If you frequently use various external hardware devices, or even if you have upgraded one component, the old hardware information is still in the registry. Advanced Hardware Editor allows you to remove non-existant devices from the registry in a much more friendly manner than using a registry editor.
In addition to simply removing devices, you can change advanced settings and save them to modify the way a piece of hardware works. Advanced Hardware Editor also comes with the ability to backup the registry and undo your changes.