Rather than necro couple year old thread I figured I should just make a new post in case others had the same issue I was and couldn't find an answer. I had the issue a couple months ago when I got Doom3 to try it and decided to give up figuring it was something with Steam version etc. Trying the Stand Alone 2.0 I had the same issue. I was able to launch the game and change game settings (which were muddied) but after I chose to restart the game the screen would be black and could hear the flicking over menu options with the mouse. In order to see the game again I had to delete darkmod.cfg (and run tdm_update.exe to replace it). After looking through old posts (and trying one? FAQ) I couldn't find the answer but did figure out through trial and error that Anti-aliasing was the issue. I have an AMD 5850 and in the Control Center>Gaming>3D Applicating Settings I found that under Anti-aliasing the Filter "EDGE DETECT" was the issue. I could set it to Wide Tent or Box and leave all the other settings alone and The Dark Mod would work. Hopefully if you have the issue you can find something similar in your cards settings. Also for me at least aliasing is limited to x8 in game so just set it to that instead of x16 just in case. The other little issue I had was the training mission not downloading and Tears of St. Lucia not loading after a save. However trying to download training mission and restarting did clear up the muddied menu settings. Anyway found out I had to rename and move the folder which I had so far left where it downloaded. So moving it to C:\games and renaming it simply "darkmod" (and probably running tdm_update.exe which was down the previous day) solved those issues. I don't appear to have any other issues so thanks to the folks who made this! hoping to dive in asap!