hi
i dont know if this will work and i know you use windows 7 but...
years ago i used to play a game called Neverwinter Nights i had a similar problem with jerky video...
i looked through the internet and found something to do with the paging file system. I increased the paging file to its maximum size on my computer and when i loaded the game the video which was once jerky was perfect
now i dont know if that will help but....
good luck