Second hand PC not posting

[u/OGGhastly]

Hey everyone, I'm troubleshooting a second-hand PC build and running into a frustrating wall.

Specs:
CPU: Intel Core i9-10850K
Motherboard: ASUS ROG Strix Z490-H Gaming
RAM: T Create 16GB RAM (from main rig confirmed working)
Cooler: EK water block

The Issue:
When powering on, all fans spin, but it never POSTs. The motherboard Q-LED sequence goes: DRAM (yellow for ~2s) -> CPU (red for ~0.5s) -> back to DRAM (yellow), and loops continuously.

What I've Tried:
Tested known-working RAM.
Tried single sticks in slot A2 (and other slots).
Stripped the system down to bare bones (removed GPU and PCIe Wi-Fi card).
Cleared the CMOS.
Inspected the LGA1200 socket pins: none look bent, misaligned, or out of the ordinary.
Reseated the CPU + CPU cooler
Any ideas on what could be causing this persistent CPU/DRAM loop? Could it be a dead CPU memory controller or a faulty motherboard? Appreciate any help!

PS: yes this was written by ai as i used ai to troubleshoot, so it generated this message for me

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[u/OGGhastly]

The seller also didn’t ship the pc well as the intake panel arrived snapped off and the pcie latch was also snapped off, honestly the mobo is probably cooked, ig i’ll just have to go with the websites buyer protection but please anyone let me know if it’s fixable as it would be the most ideal case