Problem with G33-MS2 MB

Hello all. I have a very strange problem with a G33-MS2 mobo, PDC E2160 SLA8H and a stick of Elixir 1GB DDR2 800 memory.
The board turns on, runs for approximately 30 sec, then turns off. The PSU starts to turn on and off in a second. It continues until I stop the PSU from it's power button. I have tried with three different PSUs - 2 Fortron 300W PNR and ISO 450W. All of them are working fine on other machines.
I am running anly the motherboard, CPU, it's fan and a stick of memory.
The mobo is with the latest BIOS - F7J.
Any help will be appreciated.

Build outside the case only with motherboard, beeper, cpu and power. Listen for beeps. Add memory listen for beeps. Add the video card and listen for beeps.
Whenever you don't get beeps, means there is a dead part somewhere.

...good "rule of thumb" (pun intended...) Other than the CPU, if you can't keep a finger on it - it's too hot!

Used to have an actual guide for this, had a list of temperatures graduated by how long you could keep which finger on it ...little fingers are more sensitive than index fingers - thumbs are 'nearly numb'... Have to see if I can find & post it - seems to me that the accompanying comments were hilarious!