You'll need to provide a lot more information then that since we have no idea of the system and components you're working with.
1| Can you please pass on your full system's specs inclusive of your OS and peripherals connected? If a prebuilt, then pass on the make and model number.
2| Have you made sure you followed through with
this guide while building your system? I apologize if I've failed to grasp the issue since it looks like a newly built system that isn't powering up.