New computer power issues

So I just built a new computer. I have everything installed correctly so I assume I have checked and rechecked and at first my power supply wasn't sending power to the mobo which after a small trouble shooting I found that issue. Now the computer comes on but shuts off about 10 seconds later. The cpu fan seems to be running at a reduced speed and the psu fan isn't running at all. Is this a bad psu out of the box?