I supposed to have Comcast High Speed Internet, but my computer is slow. With just the components that came with this computer, it is high speed. But since I have added SP2, McAfee Security, windows defender, this computer is very slow at times, especially when I turn it on and log in. It takes a long time until I can click IE 7 which I downloaded 4 days ago. What do I need to do to speed this thing up?