New PSU, computer shuts off on ita own

Today I received a new PSU and CPU in the mail. The PSU I got is a corsair HX850 and the CPU I got is an AMD FX 9370. So I installed my new hardware and I turn on my computer and all fans and lights are on and spinning. It's does this for about 6sec then shuts off on its own. I've made sure that everything is plugged correctly and making sure that I'm not missing anything either but it doesn't want to stay on. I even plugged back in my old PSU back into everything and the same thing happened. Is there something I missed? Is it not as simple as replacing the parts and turning on your computer, aside from the drivers? I tried removing the battery and resetting the BIOS but the same thing happened. The thing that I've noticed is that the longer the computer is off the longer it takes for the computer to shut off. Last night I went out for a few hours and when I came back I booted it back up and I got to the desktop and searched the web and everything for about a good 5 minutes and then it shut off again. Once I tried turning back on right after that it shut off after a matter of seconds. The same thing happened this morning while the computer was off all night.

Sounds like a problem with a PSU. Can you take out the old PSU but leave in the 9370 and try the computer again after reinstalling your old PSU?

yeah I tried that last night, the same thing happened even with the old one.

This is just a long shot, But try re-doing the thermal paste and be sure to use the pea method. Those 9370's run notoriously hot. Go through the CPU installation process from the start. Be sure to TOTALLY clean off the old paste off. Also, be sure the sticker from the cooler was removed. You may have already done this, but checking never hurts.

which mobo do you have?

sounds to me, that the cpu is not seated properly.

I have a Sabertooth 990FX which can run my new CPU.

http://www.techpowerup.com/mobile/190059/asus-offers-full-support-for-amd-fx-9000-series-cpus-with-existing-990fx-boards.html

I have it all figured out now though. I needed to update my BIOS and everything running fine now.