My friend's Dell mini-laptop with Windows 10 is hung up on an update. There is a blue screen stating 86% complete and do not turn off the computer. It has been a few days now. She has powered down manually and the blue screen came back. I told her to try pressing F11, and now the machine is talking to her: windows update 86% complete. I read that she can get to safe mode by manually interrupting boot three consecutive times, but then what?