Diagnosing a Sudden PC Shutdown: Is My GPU the Culprit?

Recently, I faced a rather frustrating setback while gaming. My PC unexpectedly shut down during an intense moment in World of Warcraft Classic, and ever since, it has refused to power back on. I’m seeking advice to help troubleshoot what might be wrong.

Current Setup

Here are the specifications of my system:

• CPU: Ryzen 7 3700X (recently upgraded, but used)
• GPU: RTX 2070 (Inno3D TwinX2, approximately 1.5 years old)
• Motherboard: MSI B450 Pro Max (around 2 years old)
• RAM: 32GB DDR4
• Old PSU: 600W
• New PSU: 750W

The Incident

As I was engaged in a 40-man raid, amidst a chaotic boss fight, my PC went completely black. Initially, I checked the power socket, which was still functioning with other devices. After that, I replaced the power cable for the PSU but to no avail. Given that my old PSU was over six years old, I suspected it might have finally failed. Thus, I purchased a new, more powerful PSU to eliminate that variable.

Upon connecting the CPU and motherboard, I was relieved to hear the fans whirring to life. I proceeded to complete the PSU installation and connected everything else. However, when I attempted to power the PC, it was completely unresponsive—no lights, sounds, or activity.

In a bid to further diagnose the issue, I unplugged the GPU and reconnected the PSU cable. To my surprise, the fans spun up again, leading me to suspect the GPU might be the problem.

Testing with an Alternative GPU

To test my theory, I installed an old GPU I had lying around—a GT 9800 (which is relatively outdated). Much to my relief, the system powered on, indicating that the GPU likely caused the shutdown. I was confused; it had been functioning perfectly before, and now it appeared to completely disrupt power to the system.

Seeking further validation, I tested the malfunctioning GPU in my neighbor’s PC, which has a similar configuration. Unfortunately, the same issue arose: a complete failure to function. This reinforced my suspicion that the GPU was blocking power to the system upon connection.

I remain hopeful that the issue could also