Re: Red Alert 3 Resolution won't change.

I haven't seen this myself, perhaps it's related to the extremely high resolution. Do you get the same situation when you choose more modest ones such as 1680 by 1050 or 1280 by 800.

I'm also not sure if it would work, but it may help to try forcing a non-standard resolution. You can find a small tutorial to do that here:https://help.ea.com/article/changing-the-resolution-for-red-alert-3