I installed the updated demo after installing the full game. Windows got confused and gave pririty status to the demo and when I uninstalled the demo, windows has stayed confused. I downloaded a Ut2004 Mod that was self-installing but windows couldn't figure out what to do with it. Is this some sort of registry mixup and is there a utility or a way for me to correct the confusion short of reinstalling.After a while I figured out to use the setup file to open the program mod and it is installed but I would prefer to resolve the issue anyway
Do a full uninstall. Delete the UT2004 Demo file and all of it's contents, Clean out your prefech folder (C:\Windows\Prefech) and then do a reinstallation. Should work.