Two hours ago my son had the system working and was watching tv. We shut the system down to run an errand and when we came home turning the system back on, there is no video output. Not from the cable box,or the dvd. Audio comes through fine.
Where do I begin to troubleshoot this one.

Well I'm adding this note since I somehow through a power cycle and reset and a few prayers and swears regarding the oldest part of the system (the tv) its working again. Weird.

The things I'd check first are the most basic: make sure the TV is on the right input, make sure the TV is on, and make sure all of the connections are still in place. Those are all the things that I'd expect tech support (Outlaw or your TV) to ask right off the bat. If all of that works, I'd also try connecting the cable box and DVD directly to the TV to make sure nothing's gone awry there.