I think the fundamental problem with your scenario is that quantum events are, I believe, totally random. That is you simply cannot predict their outcome regardless of the amount of data you have. So your computer would be unable to determine the outcomes for a ton of quantum events and so your predictions will become increasingly unaccurate. This is basic chaos theory, and is why it is so incredibly tough to make computer simulations for very complex systems. Even being off by the location of a few photons will rather quickly destroy your model of the future.

Stephen