Yes, both seem to have a problem with the board itself. Try googling "dfu" mode or how to reflash the small uC that does the serial communication.
You should put the board in dfu mode first. Read the instructions carefully
8u2 is the small uC, not the big atmega. Yours have that one too
Please enter a valid email to subscribe
We need to confirm your email address.
To complete the subscription, please click the link in the
email we just sent you.
Thank you for subscribing!
via Egeo 16