After installation of Windows Insider build 17686 the Lock screen appears for one second, winks off and back on, continuously.
The system does not respond to keyboard input. I have not been able to get it into Safe Mode. Unplugging the keyboard makes no difference. I am not able to RDP to the system while it's winking I unplugged my one USB disk drive no help.
I tried recovery USB media and asked it restore the previous version of Windows but it said there was a problem.
Resetting the PC is not an option because it has some fairly expensive software on it that is hard to replace.
Help! My Dell XPS 8700 desktop is a doorstop