"no input detected" on monitor with working GPU

[iwishiwasaneagle]

The monitor doesn't detect a signal when trying to boot the PC. It ran fine for a few years, before now. No post message, no beeps (speakers where turned on), keyboard and mouse LEDs are off, mechanical parts (fans, HDD, DVD drive) are spinning at normal speeds.

It seems to me either the CPU or Motherboard are broken but I don't have the knowledge to narrow it down even more.

Info:
- PC has shut down multiple times in the past, I assume due to overheating (I've tried to tell my brother to upgrade from the stock cooler... alas)
- MSI 970a-g43 mobo, AMD Saphier HD 7850 (as far as i can remember), 8gb of DDR3 RAM

Things tested:
- Monitor works with the same HDMI cable plugged into a laptop
- GPU works in another system
- Different (working) GPU experiences the same issue when installed
- CMOS has been reset
-

 

[jojesa]

Have you tested the PSU?

 

[iwishiwasaneagle]

Hi, I've just tested the PSU and RAM, and both are working correctly

 

[jojesa]

Hi, I've just tested the PSU and RAM, and both are working correctly

That looks like a motherboard issue but there is a slight chance that the CPU died.
You will have to test the CPU on another board or place another CPU on the MSI 970a-g43 motherboard.

 

[iwishiwasaneagle]

That looks like a motherboard issue but there is a slight chance that the CPU died.
You will have to test the CPU on another board or place another CPU on the MSI 970a-g43 motherboard.

I thought that might be the issue... I've ordered replacements for both for testing. Thanks for your help!