My suggestion would to be to type in dxdiag in your run or search with vista and send it to support with an explanation of what is happeneing.

well my video driver is fully updated, and i used to play this game loads, but all of a sudden i cant run it, so nothing should have changed

EDIT: Ok so this is wierd, i plugged my laptop into my tv so im running dual screen, now it works perfectly, for some reason, i cannot play demigod out of dual screen.....

You could try editing your game.prefs file(document\my games\gas powered games\demigod).  There is a line for resolution that you may need to change if it stopped working.  If you changed your display setup, the saved resolution that Demigod is trying to load my not be compatible with the monitor you've switched to.  The line in the game.prefs file looks like this:

primary_adapter = '1680,1050,60',

Try changing it to a basic resolution that any standard monitor can handle(primary_adapter = '1024,768,60',)

Simply deleting your game.prefs file will accomplish the same effect; only it will reset all your game settings as well.