If you already have the retail version of UT3 you can avoid having to download it again when you add it to your Steam account, this will save you downloading about 8.5GB of data. 1. Install UT3 from your retail disc if you don't already have it installed. 2. Make a copy of your UT3 install folder somewhere else on your hard drive. 3. Un-install UT3 via the windows control panel. 4. In the main Steam window click on the "Activate a product on Steam" button and enter your UT3 serial number 5. UT3 will now start downloading from Steam, allow the download progress to get past 2% and then pause it. 6. Copy the UT3 files that you made in step 2 to \Valve\Steam\SteamApps\common allowing it to write over the files that are already there. 7. Right click on UT3 in your Steam games list and select properties and then click on "verify integrity of game cache" and wait for the process to finish. 8. In windows explorer right click on the Unreal Tournament 3 folder in \Valve\Steam\SteamApps\common and uncheck "read only" in the attributes section and apply it to all files and sub folders when prompted. You should now be able to launch UT3 via Steam, it will go through the Direct X and C++ install procedure the first time you run. My apologies for anyone who might have tried the last procedure I posted here that I got from the Steam forums, if you run step 8 it should fix things for you.