I'm having aspect ratio issues with Thief

[Kyrith_Ranger_Pso]

I just bought the Thief Collection off Steam (awesome games, I'm so happy Steam is finally carrying them so I can finally get a chance to play them) and the games (at least the first 2) are made to run in a 4x3 aspect ratio, but my monitor is 16x9. Does anyone have any idea how to make those black bars appear so the game doesn't stretch to fit the whole space. I have an nVidya 570 graphics card, and a 20 somethin' inch 16x9 1080p monitor, thanks in advance.

EDIT: I've tried all the scaling options in the video card's display menu, they don't do anything, they all leave the game stretching to fill the entire screen no matter what the aspect ratio or game resolution is.