Let us assume we have a
being that is
omniscient, knowing
everything. This being knows the
state of every
atom, every
electron, at every
moment. This includes the
future, as that is part of everything. If it doesn't know the future, it's not omniscient.
If it knows the future, it doesn't know it in probabilities, because that's not knowing. It knows with complete 100 percent certainty exactly what will happen at every moment from now to the end of time. (if there is one).
Which means that all possible choices have their outcomes already known. This being knows what you will have for dinner on April 1, 2000, what you will wear to bed on June 12, 2002, and when you will die, and nothing can change that. You can't choose differently because you can't choose.
This is enough to mean there is no free will. You're not really choosing freely if it can be known what you will choose, you're forced into it by some means. This doesn't mean you don't feel like you're choosing, of course.
But if we assume this omniscient being is also the creator, then we get into even more interesting philosophical territory. Why? This creator, being omniscient, would have known everything - including all choices all beings in a universe would make even before making that universe. So, in a manner, it would be responsible for every action performed, since it knew what those actions would all be.
An omniscient creator leaves no room for free will, or for responsibility, for that manner, for he chose the path everything in that universe would take.