Press ALT + KEYPAD 2, KEYPAD 1 during game play to display the console window, then activate the following cheats by entering the corresponding codes:
CHEAT FUNCTION - CHEAT CODE AI responds favorably to requests; also to others controlled by AI - yesmen Buildings completed in one day - instantconstruction Money - cash Prestige - prestige Goods and money, defaults to 1000 if no value specified - goods Officer points; can recruit as many as desired - leadership Research completed in one day - instantresearch Set countries plurality - plurality Socialist government available - event 1000 Communist government available - event 1001 Anarcho-liberal government available - event 1002 Fascist government available - event 1003 Gain Prestige or Improve Relations with neighbors - event 4402 Lose Militancy - event 4305 Lose Consciousness or Gain Social reform, no unemployment subsidy, or gain social reform extended subsidy - event 3401 Gain support for extended subsidy or acceptable minimum wage - event 3403
Note: This procedure requires editing a game file; creating a backup copy of the file before proceeding is recommended. Start a new game with any country. The best choice is the one that is currently occupying the unselectable country that you want to play as. Note the provinces and their current owner. For example, assume you want to play with Croatia. Croatian provinces belong to Austria at the start of the game. Use a text editor to edit the files in the "history\provinces\austria\" directory in the game folder. All the Austrian provinces' files each have a number. The Croatian files are from 770 to 782 (for example, "771 - Zagreb.txt". Open each file and they should have entries similar to:
owner = AUS controller = AUS add_core = AUS add_core = CRO add_core = HUN add_core = YUG trade_goods = timber life_rating = 35
Change the owner and controller to your country's code (for example, CRO). Start the game and you should now be able to select Croatia at the beginning.