Weird issue with new PC Build

[legalis]

I just put together 2 new PC's for my work office, and 1 has a really strange issue.

I3
Asrock H61 MB
4GB RAM
320GB HDD
400W PSU

Pretty standard
What it does is:
Boots up fine, ran Win 7 install, software, etc.
When you power it down, all good
Press the power button, the CPU and chassis fan spins up, looks like its booting for about 3 secs, then seems to power down, fans spins off, then it tries again. Keeps doing this. If you pull the power or switch the power off on the PSU, then back on, she boots perfectly....Temp is ok in BIOS, doesn't seem to be any issues. Green light on the board (means ok). Has anyone had this issue before>

 

[wintermint]

What power supply are you using? That may be the problem.

 

[dextermat]

Hi,

1- test with another psu to see if its defective

2- verify that cable and components are well seated

3- If none of this work, try loading default Bios.

Good luck