Question Blank screen after OC - no luck with CMOS

[Bloch_]

Hi, I'm using a 5+ year old PC, and it has recently started not showing anything on any monitors on boot.

I activated OC Genie II in BIOS 2 days before it went permanent, and have manually overclocked my monitor using Nvidia's control panel (and CRU).
I have also flashed my BIOS a couple of months earlier, but have had no noticeable problems with that.

Things I've tried:
Win+Ctrl+Shift+B
Plugging all cables out
Reseating all easily removeable parts
Replacing CMOS with a new battery (also clearing CMOS with the jumper)
Spam restarting to enter WinRE (no luck)

Before the issue became permanent, and it would boot, it would sometimes say something along the lines of: BIOS config failed (or OC failed, not sure) press enter or f2 to enter setup or boot with default config

Specs:
mobo: MSI Z77A-G45 (MS-7552)
gpu: 2060 3 GB
psu: Corsair HX850 (75-001219)
cpu: 3770k
monitor1: Benq XL2420t (old version, overclocked to 140 hz)
monitor2: some old ASUS 1680x1050 60 hz monitor, which is connected to mobo's DVI output and configured in BIOS
projector: Optoma 144x

 

[rgd1101]

test with the gpu out and just the igpu?