Sad smiley on screen :-(

[rahulmanutd98]

While updating to windows 10 mobile preview,my dad's Lumia 625 restarted and then came the gears icon and the smiley :-( the phone restarts again and same process continues.Should I reset?soft or hard? What's the difference?

 

[ven07]

Got a blue screen of death installing Windows 10 Mobile? Here's the fix! | Windows Central

 

[rahulmanutd98]

Now if has got a power symbol along with gear icon,it stopped switching off,smiley is gone noe.This happened when I tried to hard reset

 

[ven07]

Do a soft reset (press volume down and power button at the same time, hold until phone vibrates and let go)