I've been trying to play games like Red Faction and Nosferatu in their original 4:3 aspect ratio but for some reason they're displayed to the left of the screen. Is there a key binding or easy way to center the image on the screen? Thank you.

If you're using an Nvidia Card, check to see if in the Nvidia Control panel, under "Adjust desktop size and position" the "scaling mode" is set to "aspect ratio" and "Perform scaling on:" is set to "GPU"

ATI cards should have a similar setting as well.

This may help in some games cases

This. I've never had it not work fine and be in the middle. Can also set a custom resolution for something like 1920x1440 so you get the benefits of native resolution for the most part. If it's an old game without higher res support you can use pixel scaling on something like 720p for a good image.