I just got an MSI Z77 Mpower and installed it, when I plug it to power, the power boutton is turned on "green", but when I try to push it to start the computer or push the main power boutton, nothing happens.
It could be the PSU or its connectors. I have the 525 version of that CM PSU and I found out after I bought mine that the CM Extreme 2 line of PSUs is cheap and under powered.
On mine, the 4 pin connector for the 20+4 pin MB power connection does not have a latch to make a sure connection to the MB. Are you certain that this 4 pin connector is plugged in solidly?