Which one was made first? Cause maybe the xp version was made so that it would work on xp, rather than the vista version being made so that it works for vista.
If the vista version isn't the original, and it was made for vista, it may not work. It seems like this would be the case since the xp one is cheaper and is probably the older one.
So basically the vista version wouldnt be need if the xp one could play on vista. So hopefully the xp version was made because the vista one couldnt play on xp