Please help me... every time I try to download something it will start and then halfway through the download an error message will come up "The application failed to initialize because the window station is shutting down". Why is this happening? I can't even download Firefox. All download boxes in security are checked as enabled. What else could it be?

See if this helps

Start>run>msconfig>OK.
Click on startup and in the list uncheck "reader" and apply