Hmm take your card out and examine it and make sure the fan is working. And if its not it probably overheated and somthing either melted or shorted out. But your computer not being able to produce video is a sure sign that its busted.. i hope it wasnt a newish buy for you. =X
Aw poor PS3, love sony but they really need to step up on pumping out some better titles before making rash moves.. Defeating HD-DVD was a start but they shouldnt be cocky.. meh.