Garmin
Thawing Procedure
for EDGE 305

This From Garmin Tech Support - Works Great!!!
You will want to perform the following restart, to "thaw" the unit. If you start with the unit powered off. Start by pressing and holding in the MODE button. While holding in the MODE button, also press and hold in the RESET button. Hold both of these buttons in, and then tap on the power button like you normally would. If the unit doesn't power on, release both buttons, and try power again. If the unit powers up, simply plug it into the USB cable, and let it charge.