Yeah, so it's vsync broken or something. You should wait for a Vsync Patch for it (if it's still being worked on), so you can play fullscreen (my netbook runs the latter Touhous at 62fps, but it's hardly noticeable so it's no problem, compared to 75fps). Btw, this is kinda basic but do you have your videocard drivers and DX up-to-date?