Something fried. I had that happen twice in the past with my Lexicon sound controller (installers fault).
The Lex was placed in a cabinet without enough ventilaton, overheated, and sent pure power throughout my system. It was a very expensive lesson because most of my speakers melted. I don't know your specific situation, but I do know that heat is the enemy. The rest of the posters gave you good advice, and unfortuneately if it isnt a heat problem, then start with your audio/video controller (rogers?), and continue through a process of elimination. Good Luck.