Conquest - description from Softdepia.com:
Conquest is a version of the board game Risk for Windows PCs, HandheldPCs and PocketPCs. You fight against up to 7 computer controlled opponents to take over the world before you are eliminated by your enemies. Each computer opponent has their own personality, which you can customize or add to by editing the players.txt file. The Artifical Intelligence of the computer opponents is particularly strong and you'll have to fight hard to beat them!
Conquest is a "Free to try" program. You can download and try it for an evaluation period.