Haven't bought a new PSU yet, managed to track down a friend with a known working PSU (650W Antec, don't know exact model). Same problem, it powers up but cuts within a second as if it is telling me something is wrong.
What I have tried:
Reseating CPU (with new thermal paste, used Arctic Silver 5, cleaned old off with ArctiClean).
Breadboarding with just 1 stick of RAM (known to be working).
Worked my way through the thread posted above.
The CPU fan does spin for the brief moments the system has power. CPU in question is a Q6600.
Any ideas what else I can try, or am I likely to have to fork out a new motherboard? I don't know anyone who has a motherboard that is compatible with my CPU.