RarelySpoken

Had a bit of a fun this morning troubleshooting my almost 5yr old PC. It's a media centre/gaming PC, ie. it's hooked up to the same TV I watch blu-rays on etc. Apart from the occasional crash, its basically ran flawlessly since I built it in Summer '14.
 
(TL;DR - I think I've fixed it, skip down to the bottom if you don't want to read my ramblings.)
 
So I turned it on this morning, and the TV had no signal, TV would immediately go into standby mode. Makes testing difficult, so I dug out an old monitor & hooked that up. No signal. Think to myself, must be the graphics card, so I swap to onboard video. Same issue, no signal. Starting to worry now, so open up for quick visual inspection. CPU cooler fan, case fans, GPU fans all spinning, so they are getting power at least. So unplug GPU entirely, no change. At this point I unplug every USB etc. so its just the mouse & kb and then remove a stick of RAM (have 2x 4GB).
Success, it boots to desktop. Before patting myself on the back too hard though, I do a restart and I'm quickly back to desktop. But then I do a full shutdown. Then on power up, back to no signal. Confusion takes hold, and after swapping the 2 sticks between all 4 slots, it keeps failing on a full shutdown/power off. At some point I realise that while I'm mashing the delete key trying to get into the bios, the spare keyboard I'm testing with (Microsoft 600) is missing the Numlock LED indicator, very odd. 
 
So I start googling, and after a few false trails find an old reddit thread. Same issue, same motherboard. So at this point I feel like it's narrowed down to the motherboard. Thread mentions updating bios, but I can't get into bios, even on a restart after RAM shuffling. But my last hope is the Gigabyte App Center. I tried to use it when I first built the PC, but on the original BIOS it never loaded. But I was on F7 now, and it installed and ran this time. So I load it up, install the @ BIOS software and attempt 'Update from Server', it seems to install but keeps it at BIOS F7...
Slightly crushed, at this point I start looking for used z87 & z97 boards, hoping to transfer my old 4670k over. Slim pickings, mostly 'un-tested' listings. So no in my head I'm pricing out a new MB & CPU, and not looking forward to buying another w10 license. Last ditch effort, I move the RAM and then boot up, open Gigabyte's site to see if there are any BIOS after F7. They had F8, F9 & F10c (beta bios), so I downloaded F8 and reopened App Center. This time I selected 'Update from file', and crossed my fingers (I renamed file from a .F8 extension to .bin, not sure if that was necessary). It installed and on a restart, it seemed to now be version F8.
Did a shutdown, and to my surprise this time it managed to get to desktop again. I restarted and pressing delete was immediately taken to the bios.
 
So (knock on wood) it seems to have been fixed for now. But whatever caused the BIOS issue (which it now appears to have been), if it happens again I'll have version F9, then F10c and after that I guess I'll be SOL? The only recent change I can think of was an AMD update to 19.4.1 the other day, but that may just be coincidental timing. 
Hopefully it will last long enough for me to save for a new build. I had been looking at getting a RX 580 to replace my old R9 280, but I guess it would be prudent to save some more cash and just get a new MB, CPU & PSU to got with it. 
 
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TL;DR - PC wouldn't boot, after pulling out hair, I worked out that swapping RAM modules around would enable boot (temporary though, on shutdown it would return to no boot). I eventually fixed it (hopefully it will stick) by upgrading the BIOS version from F7 to F8 via Gigabyte App Center (I couldn't get into the UEFI/BIOS on startup). Fingers crossed it will last long enough for me to save for a new build, and at almost 5yrs old, probably time anyway. 
 
EDIT: I suppose clearing the CMOS could have helped, but isn't the Gigabyte DualBios supposed to be automated? Odd that it didn't swap to the backup BIOS. Was thinking about how my graphics card has a physical BIOS switch, that would have been handy on the MB...