One other thing to try is switch graphics drivers. By default Pygame
should use DirectX for Windows XP. It's easy to check with the
pygame.display.get_driver() function. When called after pygame.init() it
will either return 'directx' or 'windb' for Windows. To select the other
driver set the SDL_VIDEODRIVER environment variable before the
pygame.init() call. It is explained, along with a code example, at the
Pygame FAQ: