The other day I updated to Windows version 1903. Things ran fine for a couple of days. Now when I turn on my PC my 2 monitors stay dark and nothing happens; I can see that the CPU cooler and GPU fans are running. LEDs are on too. Sometimes keyboard and mice don't light up.

Relevant Parts

CPU: i5-6600k

GPU: GTX 1070

Motherboard: AsRock Z170M Extreme4

Dual monitor setup: 1 HDMI, the other mDP/DP.

Things I have tried

  • looking in Event Viewer for any relevant information (nothing that I could identify)
  • switching to motherboard output (HDMI) allows me to boot and I have visuals on one screen
  • using this I was able to access the UEFI/BIOS screen:
    • it says the PCIe slot that the GPU is physically plugged in is empty
  • tried switching PCIe slot, same issue
  • I cannot rollback the update because I deleted the Windows.old files

The weird thing is that initially, I tried restarting my PC several times and once or twice I was able to boot with my GPU, but only if the DP cable was unplugged. After another restart, I have been unable to replicate this.

I have not tried clearing the CMOS yet.

  • 1
    Do you have another PC to try the graphics card in? Do you have another graphics card you can try in this machine?
    – Lawrence
    Jul 1 '19 at 7:13
  • Yes, both options are available to me but I wanted to see if there are other ways to test first.
    – turnip
    Jul 1 '19 at 7:38
  • I'd suggest you tried the Graphics Card in another system, and, while its phisically disconected, try to boot up with CPU internal graphics. Make sure they are activated in the BIOS setup. Jul 1 '19 at 8:12
  • Are you using the latest NVIDIA driver?
    – harrymc
    Jul 1 '19 at 19:45

If not hardware -- not firmly engaged into the slot, or a "baked", or failing GPU. It's likely a (shared) DMA problem (MSI-X). Your BIOS is your friend in this case. Try changing to a fixed interrupt for the VIDEO card. Ensure that your external card is chosen before the internal one, or completely disable the internal one. Windows is probably attempting to probe, and ultimately use the internal one, over your "external" one. Try other cables. If Windows, or your BIOS probe(s), and does not get a message from your cards output (monitor). The card will be discarded as an output candidate. Cheap cables are notorious for not obtaining the EDID from the monitor.

As Windows is concerned. You're best to leave the card in the same slot, if Windows ever actually worked on it while it was in that slot. Moving it to another slot will only add another variable to Windows, and make it harder diagnosing Windows.

Lastly; speed may be an issue. Ensure that the bus speed is not too fast (overclocked). Same for the GPU. This will cause (potential) interrupt "misses" on both DMA, and well as Interrupts. You might even try lowering the speed slightly to see if it helps (again, in the BIOS setup).

  • I will try all those things, thanks. Out of curiosity, if any of these suggestions are the problem, why is it only happening now? My card has worked flawlessly up until now. The only thing I can think of that I have done recently is updating Windows and enabling its new Sandbox feature... could that really mess with the card so much?
    – turnip
    Jul 2 '19 at 9:51
  • @turnip By default, Interrupts are dynamically chosen during POST to setup the hardware. Video is especially sensitive in these cases. Modern video cards are nearly as powerful as the motherboard itself. Requiring faster interrupt, and resource handling than the other hardware. If the BIOS picks a shared or busy interrupt. More often than not. Your video will be flaky, or outright fail.
    – somebody
    Jul 2 '19 at 18:10
  • As the hardware is used, it becomes warm, and cold. Causing it to expand, and contract. This will sometimes cause it to shift. Which may ultimately cause one, or some of the contacts to short, or make no contact at all. This happens more often with RAM, and VIDEO. As they tend to become warmer than the other components in the computer -- excluding the (G|C)PU.
    – somebody
    Jul 2 '19 at 18:15

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