SOLVED
SOLVED
You're dealing with a tricky setup. It sounds like your motherboard or CPU might be having issues, but you're seeing some strange behavior—lights are on, fans spin, but the system won't boot. The monitor isn't receiving any signal. You've already tried many fixes and need advice on whether to return the device. Your specs look solid, so double-check everything before sending it back.
It might help to reset and use just one stick, reposition the CPU, and look for any bent pins. And as I mentioned, ^.
We can try again if possible, since the paste is fresh. If you have time, modifying it would work best. Otherwise, just let me know and I’ll adjust it for you.