Driver Fusion is a PC management tool which aims to completely uninstall old system drivers with the minimum of hassle.
The program uses a cloud database to try and make sure it removes every single file and Registry key relating to your driver, and absolutely nothing else. But there are no guarantees, of course, and if a tool like this goes wrong then the consequences can be absolutely catastrophic (a trashed PC, basically). Don't even think about running Driver Fusion unless you know precisely what you're doing and the system in question is thoroughly backed up.
Using the program is at least fairly straightforward, fortunately.
Choose a system driver from the program list ("NVIDIA chipset", say), click "Analyze", and you'll see the files, folders, Registry keys and values associated with that driver.
If you're trying to diagnose problems with your system that might help in itself, as for instance you'll be able to research its settings. While double-clicking a file or Registry key will display it in Explorer or RegEdit. And the delete key allows you to wipe out some of all of the driver files and settings, if you're feeling brave (because, again, if you're deleting something important then it could be an absolute disaster).
And if this isn't enough then you can always spend an extra $19.99 purchasing a premium licence. This lets you check your individual devices, disable or restart them, update or uninstall a driver, back up all your drivers and so on (the Driver Fusion site has more).
Please note, the Driver Fusion installer will by default attempt to install other programs as well ("Hotspot Shield" when we tried it). If this isn't what you want, read each step carefully and choose the "I do not want to install..." option when it's presented.
What's new in v2.6? See the release notes for information.