@Jarvus
At first i coudnt also change the prirority in my taskmanager in WIndows 7,
then i noticed the button on the lower left called "show processes of all users" (when you are in the second tab should be process tab) or something.
After clicking this i was able to change the priority.
Hope that helps. Im german and on a german win 7 so sorry if you still have to guess a bit