Bench testing a MB

Hi ..I am back again...old age causes confusion so hopefully I can get a bench test resolved as soon as possible.....
Yesterday I set an Asus MB up for a bench test ..installing my i3 CPU and heat/fan...yes I have the fan plugged into the MB ... I have a case with my Energex PSU beside the MB so I connected the 24 pin and 8 pin power plugs ...and put one stick of memory in the appropriate slot? No problem after all I have done this on many occasions ....??
So I apply power and a Green (I presume LED ) domed light shines beside the PCI slots on the MB... I then short out the two power pins hoping the CPU Fan will burst into life but the MB appears as dead as a doornail....So I left it till after I had a sleep ....
Today I reread linderman's Benchtest instructions and satisfied I have it right I had another go ...BUT this time I noticed the PSU fan is not going ???

I thought surely it should be so I then plugged the PSU into a tester and powered on and immediately I heard the fan and the test showed the PSU was a goer as I knew it was...Yet when connected to the MB the PSU fan does not go..
So have I missed something ?? It has been suggested that I Reset the bios on the MB....but before I do this I thought it best to seek advice from the experts...hence my post...
So any advice and comment will be appreciated....Thanks Hk