the only thing i can think to do is eather make a shortcut of UT3.exe and add IP:Port -login=<login name> -password=<login password> -mod=..\Renegade to the end
"C:\Program Files (x86)\Unreal Tournament 3\Binaries\UT3.exe" 18.104.22.168:1337 -login=<login name> -password=<login password> -mod=..\Renegade
the IP is for the MP-Gaming sever but if you like you can replace it with the US server or take it out and use the console command open IP:Port by hitting F10 in main menu.
-login=<login name> -password=<login password> [color=White]does not need to be there if you do not use you GameSpy (UT3) login
[/color]change all the coloured stuff to your details
if that fails the install must of messed up in some way (happens some times) try reinstalling it and see if that helps (when reinstalling you must delete the Renegade folder from C:\Users\<user name>\Documents\My Games\Unreal Tournament 3)
Im not mad, Im mentally insane