After exchanging the first coolermaster real power 850w psu with another coolermaster real power 850w psu I had the same cold boot problem. Replaced with a SilverStone Zeus 850w psu the Boot problem solved. Sure glad I bought from a local computer store. Took it back today and got a refund.
I too am having the cold boot problem. Will not post fans turn on but no boot. If i disconect the power cord and let the pcu power down then reconnect the cord the system will boot up. I have no problems restarting from Windows. No other system problems.