Ps3 YLOD (Phat 40GB)

Need help people. I got a ps3 for £20 with ylod. I have followed tuts online by changing the old thermal paste for new that didn't work. Iv checked all the cables for loose connections. that hasn't worked. when I turn it on it makes a clicking sound near the power supply. Could the power supply be the cause of the ylod. I don't want to buy one if its not that.

ok since my last post I have managed to get it to turn on. The only thing is its telling me its getting to hot and turns off what could that be.

Edit - I found out im missing 2 heat sink pads. So hopefully this is the answer.

Heres a picture of where im missing the 2 heat sink pads. Would this be the thing to over heat it. http://i43.tinypic.com/2guz4oz.jpg