I got the same problem as the OP did originally.
I'm playing Resistance 2 co-op online. In the middle of a game, then suddenly... PS3 just shuts off. No red light, nothing. Switched the outlet, switched the cord, nothing.
Here's the backstory:
I got a 60 gig launch PS3. It always ran perfectly, and I treated it great. When I got GTA4, it froze on me. It was the apparent widespread bug that they replaced for me for free. I had time to back up my save games and they didn't charge me, so I was not angry. What makes me angry now though, is the replacement I got was only covered for 3 months.
The PS3 I sent in, other than not playing GTA4, was perfect. It didn't have a scratch on it, it was never put in a poorly ventilated spot. What I got back was a scratched up junky system that froze semi regularly. I really don't see why I should have to pay $150 bucks, in my mind, it's all their fault. They replaced my good system with a lemon, and my good system was screwed up because of their bug. They should be apologizing to me for me losing my save files not charging me.
I've got 25 PS3 games, 80 or so PS1-2 games. 90 blu-ray movies and at least 20 PSN games. I'm a customer they've profited off of. Right now I'm just so pissed off I don't know if I even want to pay $150 for a replacement. What I get back will only be covered for 3 months, and I have no guarantee it'll be any better than this one. Yeah, my Xbox 360 might break, but at least I'm covered for 3 years. This is a system here I paid $600 on and spend way more on for games and movies. I got one for my parents as a blu-ray player. I defended it from a lot of people who love to pile on hate for no real reason, but as an actual electronics piece it lost my trust, as a company Sony just lost mine.
Sort of going over my options. Maybe I'll sell off my games and movies and just get a new PC. Maybe I'll replace it, sell off all of my games, just rent from now on and when it breaks again, throw it in the trash. Maybe I'll just sell all my PS3 games, buy a PS2 and play those only. All I know is that if they just fixed my damn PS3, Sony would get a lot more than $150 out of me, and a happy customer instead of a pissed off ex customer who will probably never buy another Sony product again.