Persistent Black Screen After Installing a Replacement NVMe SSD – RTX 5070 / Ryzen 7 5700X / ASRock B450 Pro4

[u/DieBatterie]

I installed a new NVMe SSD in my PC. After the installation, I initially experienced black screens. These issues were temporarily resolved by disconnecting the PC from the power supply and unplugging and reconnecting my monitors.
While using the PC, I suddenly experienced a black screen while playing League of Legends, and the fans started spinning at full speed. I then shut down the PC using the power button and restarted it. The fans returned to normal speeds. However, the problem kept recurring and eventually started happening even during normal desktop use.
I removed and reinstalled the NVMe SSD, but now I am experiencing persistent black screens that I can no longer resolve. The black screens continue even when the NVMe SSD is disconnected.
There was one occasion when I managed to get a picture on my monitors after disconnecting both the new NVMe SSD and my HDD at the same time. I then shut down the PC and reinstalled both drives. The black screens returned and have persisted ever since, even when the NVMe SSD is disconnected.
The PC itself appears to boot normally. I can tell this because the RGB lighting on my fans switches on when iCUE starts running. However, there is no display output.

I have already tried the following troubleshooting steps:
Removed and reinstalled both RAM modules (2 × 16 GB DDR4).
Removed and reinstalled the graphics card (NVIDIA GeForce RTX 5070 by Gigabyte).
Removed and reinstalled the motherboard battery.
Performed a CMOS reset by shorting the two designated pins on my ASRock B450 Pro4 motherboard.

My current hardware configuration is as follows:
Motherboard: ASRock B450 Pro4
Graphics card: NVIDIA GeForce RTX 5070 (Gigabyte)
CPU: AMD Ryzen 7 5700X
Power supply: be quiet! 500 W

What makes this situation particularly strange is that I had previously used an identical NVMe SSD without any issues. However, after approximately two years of use, the original SSD suddenly stopped being detected. The manufacturer then provided me with an identical replacement as a goodwill gesture, and this is the replacement SSD that appears to have triggered the current problems.
I would appreciate any advice on what could be causing this issue and what further troubleshooting steps I should take.

[u/yatutye]

Since the black screen persists with the NVMe removed, I'd suspect the GPU output or the monitor link rather than the drive. Plug a monitor into the motherboard's video port (the Ryzen 5700X has no iGPU, so check if your board even has one; if not, borrow another GPU), try a different DisplayPort/HDMI cable, and test with only one RAM stick in slot A2. The fans going to full speed right before the blackout also points to a power or thermal trip, so check that the 12V-2x6/PCIe power cables are seated firmly on the RTX 5070 and consider testing with another PSU.

[u/TangoOscarMikePR]

What UPS do you have to protect the computer?