I have a problem with Movie Maker while I am saving. I can save a video in 480p, but my computer freezes when trying to save the same movie in 720p. Yes, my computer freezes and not just Movie Maker. My computer should be plenty to process the video. I have the 8GBs of RAM and the below CPU. Any help would be appreciated.

AMD Phenom(tm) II X4 975 Processor, 3607 Mhz, 4 Core(s), 4 Logical Processor(s)