I finished putting together a new build with an Intel Core Ultra 7 270K Plus and an Asus ROG STRIX B860-F gaming WiFi motherboard. I cannot for the life of me get it to post or figure out what’s wrong.

After putting all the components together, I tried turning it on. The diagnostic Q-LEDs flashed red (CPU check), yellow (RAM check), then turned off completely. For reference, after yellow, they’re meant to flash white (GPU check) then green (boot). If there’s an error with the CPU or RAM, in theory, they should stay red/yellow, not turn off. I cannot find any info online about what this sequence means.

Fans are spinning, RGB is on, and the keyboard is powered via USB but caps lock doesn’t work.

To clarify, I upgraded the BIOS to the latest version with BIOS Flashback straight away before installing the CPU and as far as I can tell it worked (there’s just one indicator LED but it did what I was expecting).

So far I’ve tried:

- booting from display port and HDMI from my GPU (RX 9070 XT)

- reseating GPU

- removing GPU and booting from integrated graphics (HDMI and display port)

- reseating RAM (Klevv Fit V DDR5-6000 CL28 2x16GB)

- booting with just one stick of RAM in slot A2 (tried both sticks individually in that slot)

- booting with just one stick of RAM in slot A2, no SSDs, no internal headers (apart from cpu fan and AIO pump) connected, no peripherals except monitor connected, no GPU

- as above with two different monitors

- redoing the BIOS flashback several times (redownloaded, flashed a new USB stick, etc)

- swapping out the PSU

- bought a brand new identical motherboard and swapped everything over to that

I get exactly the same result every time. Q-LEDs go red, yellow, then off. Fans keep spinning. No output.

Any ideas? I feel like I’ve tried everything except swapping the CPU.