I haven't even gotten past the tutorial due to this. I think it's due to scripted events that the game freezes, it freezes, but sound goes on, and I can alt+tab to fix it. It happened first when the nord guard in the tutorial told me to get into the keep, and I assume the dragon flew somewhere, from what I could tell from the sound. The second time was inside the keep when Radir told me to hurry before the dragon destroys the tower. It froze, but I head things crashing down from the ceiling, so I assume this was also a scripted event, this time it froze my whole computer, so I had to hard reboot.

Specs:
GPU: gts 450
CPU: intel core i5 2500k
8 gb RAM
Windows xp x84