Pixhawk does not boot

Dear Sirs, the pixhawk I have does not boot. The big central light is solid red when I connect the usb and one of the green little led on the right is switched off. I reformatted the sd and also change it but the problem is still present.

Regards
Stefano

If you browse the contents of your SD card there is a log file in there that will tell you what the problem is. The file is APM/boot.log

Also have you tried to re flash the latest firmware as sometime pixhawk boards arrive with no firmware installed on them.