After Android download the phone won't start up
Have a Samsung galaxy s4, last night my phone screen had the little green android pic with an info message in the upper left corner stating it was an official download with a version # etc. and the message "do not close target update in progress" left the phone alone, other than to plug it in to charge. This morning when I go to power it up it gets as far as displaying the samsung galaxy s4 logo and then it shuts off. is this a virus? Any suggestions?