The case front panel switches and LEDs are usually wired to a header placed at the bottom front corner of the Mobo. Check your mobo manual and the labels on each wire to be sure that you have wired the connectors properly.
If everything checks out correctly, and the system still won't start, look for the wire labeled "Pwr_Sw" or something similar. This is wired to your case power switch. Remove these wires from the mobo header. Next, find the wires for the Reset Switch, something like "Rst_Sw". The reset switch and the mobo power switch are exactly the same, just different labels and switch locations on the case front panel. Remove the wires for the reset switch and plug them into the power switch plugs on the mobo. Now see if pressing the reset switch will start your comp. If it does, you have a bad power switch on your mobo. If not, something else is wrong.
Yogi