Check the refresh rate on the video card settings. If the resolution runs lower than 50-60hz, then you should change the resolution to one that supports either of the two. My problem with the PC version is that my video card causes the game to freeze every time it needs to redraw the shadows. If I play splitscreen, the game will redraw shadows when a player reaches a certain zone, for each player playing. Splitscreen is actually poorly implemented into Sega All Stars Racing 1, I really hope they have a little more going for the splitscreen mode.