Darksiders won't launch

[Squill2k4]

I just bought and downloaded Darksiders and every time I try to launch it it goes to the "Preparing to launch Darksiders..." screen, then the screen disappears and reappears about 15-20 times before finally stopping and not launching the game. The game itself doesn't seem to be installed on my PC but when I run the file integrity check it doesnt find anything wrong. Any help would be greatly appreciated!