Instructions
Click the "Start" menu, located in the bottom left corner of the Taskbar at the bottom of the screen.
Click "Control Panel."
Click "Uninstall A Program," located underneath the the "Programs" heading.
Locate the name of the mod you wish to uninstall in the alphabetical list provided. Click the mod name and click "Uninstall" at the top of the window to have Windows uninstall the mod for you. If the mod is not in this list, you must uninstall the mod manually by deleting all its files.
Navigate to the "C:\Users\User Name\Documents\My Games\Unreal Tournament 3\UTGame\Published\CookedPC" folder on your computer's hard drive.
Locate the folder of the mod you want to remove.
Right-click the folder and select "Delete" from the pop-up window. The mod is moved to the Recycle Bin and is no longer activated in your game.