No post after switching from AMD 290x GPU to Nvidia GTX 980 GPU

[GET CARTER]

My sons pc specs:
Gigabyte GA-Z68X-UD4-B3 Motherboard
I7-3770K CPU
R9 290X Vapor X 8gb Gpu
16gb gskill ram
128gb ssd
darkrock pro 3 cpu cooler
ocz zx1000 (overkill I know)

The issue:
I removed his R9 290x and installed my GTX 980 and booted the computer. The pc will power on, lights, fans but no display/KB/mouse.

I removed the gtx 980 and plugged back in the R9 290x and it boots with no issues. So I than removed the drivers with ddu and turned off the PC.

I Plugged the gtx 980 back in and same issue as the first time. Tried switching from HDMI to VGA with no avail.

I removed the 980 and went downstairs to see if it would work in my PC. I removed my GX 1080 and plugged the 980 in and boots up perfectly fine.

Found newest Motherboard bios and did a successful flash and tried again. Still not working.


What am I doing wrong!?

 

[Yamitime]

take the pc downstairs and try the display there.

 

[GET CARTER]

Bring it down to see if a different display works with it in his pc?

 

[ko888]

Did you try clearing the GA-Z68X-UD4-B3's CMOS after installing the GTX 980?

 

[GET CARTER]

Hey,

I did not clear the cmos after installing the 980 but I did update the bios after it wouldn't work the first few times. I thought that would over-ride doing the cmos but I can definitely give it a try.

 

[Yamitime]

yes