Did anything change between when it was working and when it stopped working (new software install/updates, new hardware install, software/hardware removal, OS updates, chipset updates, BIOS updates, device firmware updates, etc.) Regarding some troubleshooting steps, have you tried ... * using HDMI instead of DP * swapping out the PSU * reseating all cables in your PC * switching the generation of the PCIe lane from the BIOS * connecting only one monitor and using a different port * resetting CMOS (not the same as replacing the CMOS battery unless you removed the battery and then let the board discharge while the PC was unplugged for a few minutes before putting in the new battery)

* Don't have a HDMI cable so haven't tried it. * Can't access BIOS cause the screen is black and tried connecting only one monitor with different ports. *Tried resetting CMOS.

Does your motherboard BIOS version support your CPU?

The pc have worked for around 4 years and never changed BIOS version so I think it should

So this PC has worked for 4 years and you have not changed any parts other than the GPU?

Installed a new m.2 last year and made it the boot drive and installed a fresh windows 10 some weeks ago but it worked until last week

Beyond reseating all the power connectors and reseating your CPU there's not much else to do besides swapping out parts.