I bought a mini dvi to hdmi cable to hook my late 2007 macbook up to my 42 in samsung plasma hdtv. It says no signal when its all hooked up so i know its reading it, cause normally it would say check cable. When i plug it into my macbook the screen flashes blue for a few seconds and goes back to normal. Under system pref's i try detect display but nothing happens. I dont think its a faulty cable since it is connecting somewhat, just not all the way. any help?