I can not communicatewith my APM2, I  had it working for years! but now it does not work. I have tried install and uninstall the latest mission planner with no luck

I have even tried to install the Arduino mega 2560 development kit from arduino.cc also no luck

Theo old driver dated 15/11/2012  has the same issue as the newer Arduino signed driver dated 4/01/2013

I have spent so many hour on this issue, the Arduino Mega 2560  in my device manager keeps coming up with a yellow exclamation mark?

all light on board are normal with GPS flashing initially then solid