no f8 to start in safe mode. If your machine hangs at this current time only option is to reinstall. I am going to setup a couple of machines tomorrow and do more testing. I am willing to help a few if you have questions, i am no expert but will try. I thank this blog for introducing me to virtual box. Never used it before and now i love it. The system hung up on windows developer preview with the circle going and going and going.