So what has happened is that the super heated solder stuff has cracked on the board. There are two fixes for this.
1) take playstation apart remove board and heat the solder with a heat gun that powers to at least 700c .
2) Wrap it in a towel and run a hairdryer into the towel until it smells !!!!
Both methods are intended to melt to solder and allow it to reset uncracked.
Oh, or pay £100 and get a refurbed one tomorrow with a new 12 month warranty from Sony.
Sounds more like a way to break it even more.
If you don't have a warranty anymore, go for taking it apart and re-soldering. That, if you know anything about soldering, is the easiest way.
Of course, theres no mod-chips for PS3, so it's kinda useless to open it for anything else. That's sad.
If you have the money, the last option is definitely your best choice.