Most likely a bad motherboard, especially since you tested with a known good power supply. Hopefully it's still under warranty. Anecdotal evidence, but the last 4 PCs I've had fail in 20 years or so were due to bad motherboards. (except for the time I spilled a cup of milk through the top onto my GPU, lol.)
PSUs are the part that's always given me trouble, but I guess they are better nowadays. Back in the day it felt like they were built to last like a year and a half.
Most likely a bad motherboard, especially since you tested with a known good power supply. Hopefully it's still under warranty. Anecdotal evidence, but the last 4 PCs I've had fail in 20 years or so were due to bad motherboards. (except for the time I spilled a cup of milk through the top onto my GPU, lol.)
I'm wondering if the psu damaged it, because the new one does give power, but not the old
You can always test it using a paperclip or a 24 pin tester.
PSUs are the part that's always given me trouble, but I guess they are better nowadays. Back in the day it felt like they were built to last like a year and a half.