Question Display receives no signal while GPU is plugged in (PSU or GPU issue?)

[SuicuneSol]

Hello,

PC was working fine last night. No changes in hardware or software. Booted it up this morning. Monitor says "No signal".

So I troubleshoot. I'm not able to get the monitor to display anything, even with the HDMI cable plugged directly into the motherboard. It is only when I completely remove the GPU from the PCI slot that I can finally get a signal from the integrated graphics.

I'm unsure whether this is a PSU problem or a GPU problem. So I decided to test some more. I borrowed a second PC and swapped the graphics cards. The first PC still has the same issue where I can't get a signal from the GPU. The second PC ALSO now has the same issue with "no signal". Frankly it makes no sense.

1st PC had 600 watts PSU with GTX 770. (7 years old.)
2nd PC had 700 watts PSU with RTX 2070 Super (6 months old). As I said, I also swapped these GPUs but the outcome remained the same.

Based on these tests, what am I to do? D: Help me Tom's Hardware. You're my only hope.

 

[rgd1101]

full system spec? include make and model of the psu

both pc using the same monitor?

 

[SuicuneSol]

full system spec? include make and model of the psu

both pc using the same monitor?

Case: Corsair Obsidian Series 250D Mini tower
OS: Windows 7 Professional
Processor: Intel Core i5 4570 CPU @3.20 GHz
Motherboard: MSI Computer Corp. Z87I AC
Power: Corsair Builder Series CX 600 watt
Liquid Cooling: Corsair Hydro Series Cooling H75 Performance Liquid CPU Cooler
Thermal Compound: Arctic Silver 5
Memory: 8GB
GPU: MSI NVIDIA GeForce GTX 770 (Twin Frozr)

Used different monitors for both PCs. (Plus the monitor for the PC in question still works since I'm using it right now.)