After update Etrex30 he does not work

HI!

After update my Garmin eTrex30 he dont work.

I tried to update him from 3.40 for 4.90 with help Garmin Express. Step 1: Download software. Step 2: Turn off your device from computer and continue installation on the device. 

I done Step 1, but when i turn off device from computer he just stop working and not reaction for any key press.

Battery NEW.

Now it only works with USB Cable... 

How change this or fixed?

Sorry for my English.