I've narrowed the problem down to the graphics driver. Running version 335.23 (default driver for windows 8.1) everything runs fine. When i try to update the driver it installs ok, but when I restart I get the spinning circle for loading windows, then just a black screen. I can't get to the login screen. I noticed the numlock light also turns off. The only way to get it back is go into safe mode and uninstall it. I just reformatted and that was no help. Any ideas? I'm at a loss, I figured a reformat would fix it.