System Build Repeatedly turns ON/OFF on Restart

swoop00

Prominent
Jan 21, 2018
2
0
510
I built my first PC in late 2013 (Haswell i3). In late 15' or early 16' I started having trouble. My PC will try to turn on and then turn itself off over and over every time I restart. I have to unplug it and plug it back in, and it works fine. It only does this during restart. I tried some basic troubleshooting and nothing seemed to work, so I chalked it up to a power supply problem. I've lived with it since.

I don't tax my PC hard and decided to upgrade rather than build new. I figured I could survive with this system for a few more years. I bought a Haswell refresh CPU and enough RAM to max out. I figured I'd pick up a modular PSU as I can transfer it to my next build and perhaps it would solve my issue. I just installed the PSU (nothing else), and tried to restart. Same issue. I'd like to get this fixed prior to my CPU upgrade because I need to update BIOS to accept the Haswell refresh. I'm concerned about restarting after BIOS update.

Any thoughts on how to solve this?
 
Thanks for the response, vapour. No screen comes at all. It stays on just long enough to hear the fans before and turns off and right back on in a nasty cycle. It's an Asrock H81M-ITX.