Mobo doesn't detect GPU

[19DeltaSNAFU]

Ok, what you need to do now is to shut your computer down properly, turn off power supply  and press the start button until all the lights go off on the motherboard which completely drains all power from system.  Remover just the power cables from the old card and hook them up to the new card, plug the cable to the monitor up to the new card, turn the power to the PSU on then start the system.  If you get nothing on the display after a few moments, just unplug the cable to the monitor and plug it back into the old card so we can go further.  The old card should still display even without power, it will draw enough power from the pcie lane at idle to work.  GO, and cross your fingers.  Read this twice and make sure you do this exactly, there is a reason for doing it like this.

[-AJ-]

I did that. Upon starting the Pc I got a high pitched sort of screetching sound (kindof like a warning sound) and no display. I turned it off again to stop the sound and put the cables back to where they were and it's now running again.

[19DeltaSNAFU]

Did you put the display cable back or power cables or both?

[-AJ-]

Both

[-AJ-]

It was a very painful sound

[19DeltaSNAFU]

Yep, coil whine to the extreme.  Ok, what we need to do now is to find out which version of windows 10 you have.  Give me a second and I'll tell you how to do this.

[19DeltaSNAFU]

Okay, minimize firefox, and on the desktop you'll see "Settings" and click, then "System" click, then "About" click and tell me what version of windows 10 you have.

[-AJ-]

Version 1511 Build 10586.713

[19DeltaSNAFU]

Good, so it's not the windows version, new nvidia cards will not work with version before 1511.  So, lets try this.  Shut down, turn off PSU, hold down start button then remover the old card and hook power and display to new card and start up.  If this don't work, shut down and put the old card back like it is now.

[-AJ-]

Didn't work. I only got 5 beeps and the d6 error code, like before.

[19DeltaSNAFU]

Okay, there is sometimes with AMD boards that you have to use a different driver version or in worst case do a fresh install of windows 10.  Did you buy your Windows 10 or is it a education version or anything different than just retail?

[-AJ-]

I got it through the free upgrade program that Windows offered. It's an upgraded Win7 installation. But I don't see how that could be a problem, as the motherboard won't even pass POST, long before Windows is booted.

[19DeltaSNAFU]

well there is this.  If you are using an HDMI, the driver is in Windows.  What cable are you using to go to your monitor?

[-AJ-]

HDMI...

[19DeltaSNAFU]

Bet you dont happen to have a DVI cable do yoiu?

[-AJ-]

hmm...let me check.

[-AJ-]

Well, my monitor has only two HDMI and one VGA port. And I don't have a VGA cable at hand right now, much less a DVI to VGA adapter or something like that.

[-AJ-]

And shouldn't the motherboard detect the GPU, regardless of whether there's a monitor plugged in or not?

[19DeltaSNAFU]

No, that's why if you'll look at why guys used to used jumpers on multiple video cards doing mining.  Take a DVI and use a capacitor and jump it from one port to another on the DIV so the card could be recognized.  Try this go to device manager and look again.  Click "view" and then "hidden devices" and see if it shows up.  probably wont but it's worth a try.

[-AJ-]

It's still not showing.

[19DeltaSNAFU]

OK, lets try safe mode, do you know how to boot into safe mode?

[-AJ-]

yes

[19DeltaSNAFU]

try installing driver in safe mode

[-AJ-]

Didn't work. The installer says "Microsoft Visual C++ Redistrutable packages for Visual Studio cannot be installed in safe mode.

This graphics card driver could not find compatible graphics hardware".

[19DeltaSNAFU]

Have you checked to see if there is a bios update for your motherboard?