I have a Lenovo Desktop running Windows 7. All of a sudden my screen froze, and some of the desktop icons went blurry. The mouse moved, but couldn't select anything. The keyboard was non-responsive. I rebooted with the Power button, and tried running System Repair, which couldn't fix the problem. When I boot up I get the colorful Windows logo, which "breathes" as though it's starting up nicely, but then hangs up at that point. What can I do to get past this hangup?