BIOS or POST error

I have bought new parts for my computer, ?ncluding new motherboard, new CPU, new graphic card, new HD and new power supply. But when I try to start it, it comes with 3 long beeps and after a while 1 short beep. And then it starts over again and again. I have tried a lot of things, but nothing wont seem to help. Then the other day I tried unplugging the power for the cpu only, and then I just started up normal. No beeps or nothing. But it wont work without power to my cpu. Does this mean that my motherboard isnt working? Or is there something I can do about it?

Thats just about it 🙂
Thanks