Picture freezing, sound continues


Anyone any thoughts on why the picture has started to freeze on my Fox T2 with the sound continuing similar to how it is in maintenance mode? The box eventually reboots.

I'm running the customised firmware and I installed a new 2TB drive recently which is not showing any errors.
Thanks, I'll work my way through the contents of the link.

Hopeully,temperature should not be an issue as I have the Fan package installed and the fan running flat out.
When I installed the new 2TB drive.

Ambient recently has been high, and is set to be high again, but at least it's as cool as I can get it.
The hard drive is at 36 now with a worst of 40 (I installed the fan package some time after the hard drive). Is there another temperature source?
I've followed the suggestions in the link above (thanks) but am still seeing problems. The most recent has been several instances of the box freezing and 'Invalid Format' being dislayed on my LG 55B7V.

I'm rapidly losing faith in the box.