Device drivers allow the CPU to communicate with proprietary peripheral devices. They store the translations to all commands that the device may send.
Viewing Drivers
Unsigned Drivers
Windows has a hardware compatibility program for drivers that work with their OS. By default, windows does not enable drivers that do not have the Digital Signature. You can still use them though, you just need to enable them.
Beta Drivers
Drivers that are latest version and untested. They can cause immense system instability.