My Phone is dead while updating to win 10 technical preview, how can I get it working again?

[Windows Central Question]

My Phone is dead while updating to win 10 technical preview.. someone please help..!

I use lumia 720.. I installed windows insider..I tried to install windows 10 technical preview through phone update.. while updating, got stuck in the middle..
its literally showing " :-( " same thing happening wen i tried restarting..

Now its not restarting as usual. What to do? please help!!!! when connected PC. phone is not detected by nokia recover tool also. please help..