Resolution problem

I was playing a game on my computer and we set the resolution to some awkward resolution like 1024 by 968 (not 768) and after 10 minutes of playing the screen looked all different colors and we shut off the computer and restart it. Now it will not go back into windows. I think it is because it is trying to load that wierd resolution and the 2 monitors we have wont work with it. It gets past the windows logo with the scrolling and then there are a couple flashes of blue screen with some white letters that happen really fast and then the computer restarts. BTW I am using Windows XP. Please help!!