CPU/Mobo PC wont start after assembly

[maddy_in65]

This is my first home built computer, I assembled it using various online videos and tutorials. When i connected power supply to electrical socket, there is no led or anything on PC case or motherboard.
I am using Corsair CX430. I afraid i have done some wiring connection wrong. Please can someone advise What needs to be checked in order to find what goes wrong.

 

[asingh]

Have you plugged in the EPS 12V and primary ATX cables in tight. Also press down firmly on the RAM and GPU docks. Usually a loose fit somewhere, if you assembled it correctly. Remove the USB headers for now to relieve the cabinet of some clutter. Also are the SATA HDD connectors placed in firmly.

 

[maddy_in65]

I am not using any graphic card in system. I Checked motherboard with only 12pin connector but PSU is not working. I am going to check it at Corsair service center.