It is possible that it is a bulb failure. Keep in mind that with rear projection TVs that they are pretty much a projector, reflective surface, and a screen. If the bulb goes out you are done. Most rear projection TVs are made under the same premise as other TVs that they are not user-serviceable. So there would be little or no indication to what the failure is.
Things may have changed more recently, but then again, who is buying (or selling) new rear projection anyway.
If there was no power at all (no sound) then it could have been a simple fuse, or maybe the power supply/transformer.