New PC - Won't Start

Okay, so to make a very long story friend and I are putting together a new computer (re-using an old CPU, SSD and RAM) but they all work. The case is a Fractal Design Artic XL and the PSU is a 750w EVGA, we have everything wired up besides some case fans but the computer will not start. You click the button on top of the case and nothing happens at all and we can't figure out what we did wrong. You can't start it from the motherboard as far as we can tell. 

Does anybody have any ideas of what to check?

make sure that the psu is on the right voltage type. there may be a switch usually a red one try it on its other setting. if that dont work theres a good chance you might have bumped one of the capaciters or damaged the mobo somehow. i did that once and the pc wouldnt boot. if your computer wont boot id bank on it bein the mobo prob got to buy a new one. also make sure you got the power switch wire connect to the right pins on the mobo.

I don't think the PSU has a switch, how could I test the motherboard without switching it out? I don't even see any LEDs on the case telling me it's getting power either. 

You can short the MB into starting by using a screwdriver across the + and - of the power switch pins on the MB. You might have mistaken the button connector for a case fan connector so double check that. If you still have the manual for the MB it will tell you what the pins do, If not you can google the motherboard model to find information on the pins. Sorry for calling them pins, I have forgotten the technical term for them.

EDIT: Its called the "System panel connectors"

Ah okay, I'll try that this afternoon. Thanks!

Sounds good. I hope it is just a button problem, if not I have no idea what could be wrong. If you took the CPU out you might have bent a pin putting it back on. Also, just to confirm, your motherboard is the correct model for your CPU right?