I am running my xbox on a Samsung HDTV with the frozen VGA cable. Now if I set 720p mode on dashboard I can run games fine through disc, however I can not launch XBMC, Evox runs fine but XBMC doesnt show and a message on the tv comes up showing check cable.

Please can anyone advise on this? My primary skin is the MC360 dashboard one.

HDTV works fine with 360 through VGA up to 1080p