The problem is most likely your a/v cord. Mine works perfect, but whenever I happen to disconnect the a/v cable, I get the red rings. Just get a new a/v cable first and try that.
P.S. I have all systems and I love the ps3, but I hate it's online play. I play my 360 more because of it's online play. The ps3 I just use it play single player games and not much into the online multiplayer. The Wii...well it's a good decoration in my media center lol