Uninstall dolby audio driver version 7.2.7000.6 download

So, probably dumb of me to do, but I downloaded a driver update, and once the thing 'updated' my drivers, all of a sudden I don't have working sound. I use the Dolby Home Theater v4. Now it says "The Current Dolby audio driver version is 7.2.8000.17 and the software expects driver version 7.2.7000.6. Please install a valid driver and software application combination." And when hovering over the sound image on the bottom right of the screen, it says "No Audio Output Device is installed". I tried to both recover as I had backed it up prior to installing everything, but that didn't work, and then I tried to roll back the drivers, and that didn't work either. I'm not sure where to find the correct driver to download and install. I'm really hoping I didn't screw this up... I got the PC for free from my boss' boss months ago, which was awesome, but I don't have anything from when it came packaged other than the mouse, keyboard, and screen. Any help would be nice, thanks.