If you notice the fan speed is slowly getting louder and louder, a fair bet is that the PS3 is getting clogged with dust, which will eventually lead to overheating and lockups/Ylods. One thing you can do is turn off the PS3, and then switch it off with the rear switch. Then, press down on the eject and power buttons at the same time, and flick the rear power switch back to on. Keep holding down the eject and power buttons until you get a beep, and then a few seconds later, the fans will spin up to full speed in reverse (very loud, sounds like a hair dryer), this will last for around 15 seconds and then you'll get a double beep and it'll do to standby.
When I've tried it on mine I noticed a bit of dust get blown back out of the PS3, but my PS3 isn't very dusty anyway. Its worth a shot anyway, Sony wouldn't have programmed it in if it didn't do anything.







