the q codes are on page a-1 at the back of the manual. 02 is a really early code, so you might just have a motherboard with a problem itself.
the crosshair 8 take ddr4 memory
i don't think the microcenter stores do support over the phone, you'd need to take it in to their helpdesk. alternatively, you can also contact asus support.
It is a very early code, but you need to consider what 'phase' it's on. Which debug LED is lit?
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