Question PC stopped POSTing after wife accidentally plugged in a monitor to the mobo port ?

Oct 11, 2021
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Hi All,

Put together a brand new PC for the wife, she used it for 3 days absolutely 0 problems whatsoever. She accidentally plugged in a second monitor into the mobo instead of the GPU and called me over after because the PC wasn't POSTing. I unplugged the second monitor and turned on the PC and it just won't post. VGA light is on on the mobo. The main monitor is connected to GPU through HDMI.

What happens:
  • PC won't POST
  • Mobo VGA light is on
  • Cooler, GPU and Mobo lights come on
  • No lights on the mouse and keyboard
  • No beeps or boops from Mobo
  • Fans spin up and work seemingly normally
What we've tried:
  • Removed the GPU and put it back (don't know why, why not...)
    • While the GPU was removed and we turned on the PC, we got a green light above the VGA light
  • Reset CMOS by changing the battery (waited five minutes before putting the new one in)
System:
  • GTX 3070ti
  • Ryzen 9 5900X
  • ASUS TUF X570 WiFi
  • Corsair LPX Vengeance 32gb 16x2
  • Corsair PSU TMX 850
  • NZXT Kraken X73
Thank you for your time and help!

EDIT: Put my gpu (1080) and it posts. I put her 3070ti in my system and it doesn't post with VGA light on. Could it be a faulty GPU?

RESOLVED: It was a faulty GPU. We returned the MSI Gaming Trio 3070ti and got a replacement, everything is running smoothly now.
 
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Remove the discrete GPU.
Plug monitor into MB GPU port.
Go into BIOS and switch GPU preference setting.
Save the setting and immediately pull monitor cable.
Let the computer reboot and POST to nothing.
Power down, install discrete GPU, plug in monitor, and power on.


Ignore. Confused posts - thought OP had an Intel CPU with iGPU.
 
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huh? how can he do that without GPU?
Oh, crap! Confused posts - thought OP had an Intel CPU with iGPU.

For a Ryzen suggestion...
Remember that you need to unplug the power and hold down the power button for a few seconds (to drain caps) BEFORE doing the CMOS reset on some boards. If the PSU is plugged in and still powering the motherboard it may not work.
 
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