If I were you I'd do the following:
1. Uninstall video card drivers. Reboot. Install video card drivers.
2. Test fullscreen and windowed mode
3. Reinstall openglr UT dlls/ini settings (follow the read me). Use opengl
4. Test fullscreen and windowed mode
5. Reinstall d3d9 UT dlls/ini settings (follow the read me). Use d3d9
6. Test fullscreen and windowed mode
7. Download fresh chicken UT and run
8. Post errors to ACE forum
What resolution are you running UT at?
Also, run dxdiag and put on
http://pastebin.com/ and post in a topic that isn't this one.