I was in the middle of gearing up for the NHL playoffs with NHL 12 and my PS3 shut off right in the middle of a game. I found that couldn't turn the system on to even eject my game.
I had a just a little difficulty with the guides as they often spin the system boards and show them from an altogether different camera angles but after meticulously following the guide (and incidentally breaking the BluRay drive cable clip off the board) I was able to successfully fix my defunct PS3 by reflowing the onboard chips with a heat gun. The parts sent were great quality and the fan now runs at a much quieter rate I would assume due to the quality ceramic thermal paste.
The old thermal pads and some electrical tape worked wonders to hold the Blu Ray cable in place and I don't blame iFixit for my fat fingers breaking the clip for a second.
Just be very patient and study each portion of the well diagrammed albeit a little confusing process. Be patient as there are a lot of parts to remove but nothing here that anyone even reading a guide on this site shouldn't try.