Make sure you have the power button connected to the motherboard.
To make sure your power button isn't the cause of the issue you can use a screw driver to touch the two pins that tell the computer to power on.
Some power supplies have a power switch on the back. Make sure it's on.
Make sure your surge protector has power and it switched on. (A good way to test is to plug something else into that same outlet and make sure it works.)
Make sure you have the main motherboard power cable connected and the secondary 4 pin motherboard power connector is connected. (usually near the CPU area)
Do any fans spin?
Do you hear any beeps?
Do any lights turn on at all?
A power supply tester might be a good option.
I have this one:
http://www.newegg.com/Product/Product.aspx?Item=N82E16899261023