There are two choices for how the Dell U2311H handles input.
Fullscreen.
4:3.
I understand that. I'm saying, keep it to "fullscreen." You should not have to change it from that under any circumstances, as long as you are using the computer as the sole video source. If the video card is upscaling properly, then it's
impossible for the monitor to override that. The GPU does not "tell" the monitor whether to upscale or not. The GPU, if it upscales properly, then it will send the monitor video data that has already been upscaled. A monitor cannot tell the difference between a 640x480 image that the GPU upscaled to 1920x1080, and an image that was actually rendered at 1920x1080. To the monitor, they are exactly the same thing.
Look at the image I posted. If you were to have the monitor stretch it to 16:9, it would be unchanged. This is because it already *is* 16:9.
Let me put this another way. Does your monitor have DVI? Are you using it? Does your monitor display pictures at its native resolution just fine? If you said "yes" to all of these questions, but you still can't get 4:3 games to display properly, then there is nothing wrong with your monitor. There's something wrong with your GPU, or its drivers, or the configuration of its drivers.