I'm having difficulty loading the blinking template to my Arduino uno

[johnwasser]

Looks like the ATmega8u2 (or 16u2) on the other Uno stopped enumerating.

boomrollkick:
So what does that mean I should do?

You can refresh the firmware on the 8u2. Google for "Arduino DFU". DFU stands for Direct Firmware Update or something like that. That's how you write to the 8u2 flash memory via USB.