7 to 10 upgrade. Stuck at Shutting Down screen after the upgrade attempted restart. Power down?

[WPCentral Question]

The install link recieved was used and the download happened, agreed to license agreement, upgrade appeared to go normally. Didn't stay with it the whole time but saw it start to do a shutdown, closed everything and then gave the message configuring updates and was at 4% but not changing for the few seconds that I watched it. Came back 10 mins later and it was showing the spinning circle and saying Shutting Down. Still like that over an hour an there doesn't appear to be any activity. Saw in a forum that you need to disable security. I have Norton and didn't do that. Wish that would have been instructions with the upgrade pertaining to that.