Removing or adding black bars in Crossfire or any other game

With my old PC, I had this issue with black bars, I was stuck with it and was forced to use a high resolution, that I didn't like.. I don't want anyone else to have this problem, so I got a solution for it.. Some people prefer blackbars (I'm gonna start using them again now), and some people wanna get them removed..

https://www.youtube.com/watch?v=79oS3I31MfY