[Al Skierkiewicz]

TTL,
This may simply be an issue of over temp on the microproc. If the box is still in warranty then opening it is not an option. There is Microsoft tamperproof sticker internal to the box that needs to be removed for entry into the box. The two fans suck a lot of dirt into the box which clogs the heatsink. Unfortunately, self diagnostics are not a big deal in Xbox so there could be something wrong with either the cable or the connector. If the box doesn't get moved and it lives on the ground or inside a cabinet, suspect the dirt. If it moved a lot, suspect the connector/cable.
There is a lot of info on the net about error messages and fixes. Choose wisely...