PC doesnt turn on with cpu in.

[dusty_11]

I tested a new build and it worked fine , but now when the cpu is in it just restarts. The heat sink spins and turns off over and over. I know the psu and ram are good I've tested multiple sets. When I press the power button with the cpu out the fans spin continuously. Any help on where to start? Thanks
I5 6600k
750w psu
1 stick 8gb ram or (2 4gb)

 

[drivinfast247]

Motherboard?

 

[dusty_11]

Gigabyte GA-H110M-A