Ok, so I  tried all the plugging and unplugging stuff, holding the power button etc.  None of that worked.   I went ahead and opened the back plate of the laptop, and disconnected the battery from the motherboard for a few seconds (without unscrewing or removing the battery).  I reconnected it, put the back plate back on, hit power...and IT WORKED!   It was super easy.  Not sure why the Dell tech advised the OP against this?  I am not a techie by any means and don't know my way at all around the actual components of a laptop...so if I can unplug a battery, anyone can. I saw this solution in some other threads as well so definitely try it before calling tech support.   
My m15 R6 is inert. The alien power button glows steady blue when the ac adaptor is connected, steady orange when not. Pressing and holding the power button for an extenced period ac adaptor connected or not, or pressing and holding with the Fn key held and pressed does nothing. Anyone with any ideas?
m15 R6, will not power on