Thank you for your reply Joe.
I have tried several different brands of HDMI cable, all give the same 'No Signal' message on my TV. Interestingly if i completely unplug the HDMI, the TV says 'No connection', when you plug in the cable it changes to 'No Signal', so its clearly detecting something. When the picture does come on, it seems like the signal is weak.
I am on the latest BIOS which is just and temperamental as the OS.
I've already had to send one of these boxes back, I hope we can figure this out without sending this one back too!
Thanks,
Max