I know just the way! Best part is, it will work for every single game you apply a 4:3 aspect ratio to, meaning its a one and done process but you can revert at any time. However, its such a clutch and simple tool that you wont ever need to revert, as your custom 4:3 ratio isnt applied when you change a games resolution to a non 4:3 resolution. Go to Nvidia Control Panel, then on the left under Display, click on "Adjust Desktop Size and Position. In here, make sure aspect ratio is the highlighted bubble, and under "Perform Scaling On", switch it from display to GPU. Boom you're done and ready to play any old school game with 4:3 ratio. Load up any game, change to a 4:3 resolution (or any non-widescreen resolution), and it will apply the borders for you.