I picked up copies on Steam for my sons to play (I really enjoyed the game back in the day, and they have been enjoying single player). I wanted to let them play against each other. However, even though I followed the steps from @Phoinix_Daevorn above, I could not get GameRanger to recognize Total War.

GameRanger has two options: Medieval Total War, and MTW Viking Invasion. It does not want to take the Medieval_TW application for either of those. I did not see any other options in GameRanger.

If someone could help me, I would really appreciate it. Thanks!