My neighbor was having issues with his PC freezing up during games, saying his CPU fan specifically) would ramp up. He then bought new parts and asked me to build him a new PC to replace it which I did (we exchange handiwork). Now he's wanting to give his old parts to a friend of his who had an even older PC. So I've got another build which was mostly parts from his old one with the exception of a new power supply and graphics card.

At first, 3/4 of the time I wouldn't get any video. I noticed he had two different sets of memory so I stress tested each set individually and in each of the DIMM slots. It all tested fine and I was getting video more consistently when only using a single set. I was using stress to test both the CPU and memory and never came across any freezing or other issues.

I've tried going into BIOS to see if any settings in there were causing issues with the mixed memory but regardless of the configuration or using the on-board graphics, I get no video in BIOS.

Now, regardless of configuration, I'm getting no video in BIOS or an OS 100% of the time.

CPU: i7-9700F
Motherboard: ASRock B364 Pro4
GPU: RTX 3070
Memory: 2x 16GB DDR4-3200 (CMW32GX4M2E3200C16) + 2x 8GB DDR4-3000 (CMW16X4M2C3000C15)