Probably 670 actually, don't know how you chose that close...

The computer won't start without a working CPU. I know this cause when i exchanged the mainboard for my brother (the old one died) i forgot to plugin the CPU power cable. It never started, it gave no signals, like dead.

But it worked fine with a CPU?

If you are missing components, that is the issue.

If you have more components coming soon, I recommend that you stop and wait for them to arrive before doing anything else. Making a hardware change of this caliber will require that you reformat / reinstall your O/S -- so even if you use your old Harddrive, you will notice you're stuck in a boot loop until you redo the operating system.

No OS installed either <object class="emojione" data="https://resources.enjin.com/1489581540/themes/core/images/emojione/svg/1f61b.svg?0" type="image/svg+xml" standby=":p">:p</object>

yes.

Ah glad this has been cleared up, I have an intel i5-3570k on the way :3

For the computer to pass post you need the basic components in the pc - This includes the processor....

Don't expect it to do anything until you have all the components and O/S installed.

Odarus you are wrong.... You dont need any OS to start a computer. Its running with the BIOS menu then.