Hp 8200 Elite Intermittent Boot Issue

I have a super weird problem here. I have an HP 8200 Elite Small Form Factor PC running Windows 10 with 4 x 4GB Patriot RAM DDr3 PC10600 modules installed. Last week it wouldn't boot, it would turn on and I could hear the HDD running, mobo light was green, but it wouldn't POST, and after about 90 seconds all the fans (including the power supply) would spool up to rocket ship levels. If I removed all but one stick of RAM and rebooted, it would boot. I could then shut down and add the other 3 sticks and it would boot and recognize them within the OS once running. Problem was, if I shut down and turned it back on, it would work, but if I restarted instead of shutting down it wouldn't boot, and I would have to pull the RAM again and go through the same process to get it going again. Coincidentally, due to a completely unrelated issue, I tripped a breaker, and had to do the RAM reset thing again. After that, I tried just holding the power button down until it turned off (while fully booted), and found I would have to do the RAM thing again to get it going. I've also noticed it won't let me get into the BIOS from the POST screen, which has me thinking it's a BIOS issue, and it's running version 2.31, which is an older one. I'm concerned though that if I try to update the BIOS, and it restarts and won't boot again, the update won't complete and I'll brick the thing. Anybody have any ideas on this? Thanks.

 

Update - I was able to get in to the BIOS. Reset to default settings, no change.

 

Have you tried the 3 sticks but only 1 at a time. I have a 8000 sff with winn 10 x64 running with 2g and can't tell the difference. I had a 4gig went bad.
I did have to move the good ram to the proper slot for a cleann boot.

 

Yeah same thing no matter which stick combinations I use... My gut is telling me BIOS. There's an option to flash it from the actual BIOS screen (instead of using an .exe in Windows), but again, I'm worried about it not restarting properly and getting a partial installation.