This question follows on from this one:
I thought we had fixed the problem but it has returned!
I am using an Asus P5B motherboard with Pentium 4 3.4 GHZ 775 processor and 512MB RAM. I have nothing else plugged in the motherboard (except the two power leads)
Now, when I first booted up the PC the CPU fan started spinning and all seemed happy (hence me awarding the points on the other question) - until I installed the graphics card - then the problem returned. (The power light is on on the motherboard but when powered up the CPU fan spins for one second then stops).
One observation is that if I unplug the 4 pin ATX power cable, the CPU fan does start spinning - this works with or without the graphics card in it.
I think the power button was faulty on the other case (I have got a new one now) - so I think there may have been multiple problems.
As I said before this PC is for our CEO at home and I really need to get this sorted quick! Hence another 500 points on offer.