Won't boot - very interesting matter

[vlajkomaster]

After pressing power button I see motherboard title but nothing after that. EXCEPT when I hardly push mother board on some place in the middle. I need to hold this until system booting is complete and then all works fine. This is my checked method for last 6 months, but I'm worried about everything and that pushing. One more note: during, for example, appearing of 4 Windows 7 lights, if I release to push it, they stop, hard disk stops to work, and just after that if I push again, all continue to boot. It seems as if some loss of necessary contact on the board that detect hard.

I checked all: memory, graphic, replaced hard but not checked power supply but I don't if it's about that. So when system is started all works fine, games, software etc....

What this could be and should I change motherboard?

Thanks!!!!!

 

[alexoiu]

Try testing the board outside the case (on its box). See if still the same.