Asus Motherboards will not boot. CPU fan spins for 5 seconds then stops, no post, no beeps. Have tried multiple CPUs, multiple RAM sticks, multiple power supplies, and 3 different Chassis. I've also bench tested this (MB/CPU/RAM/PSU) without success. This happens with 5 motherboards, all the same type, brand new from ASUS: Z370-G. I've swapped all the components I can think of. Any Experts can think of something I missed? It's hard toi believe an entire box of MBs is bad, but seems to be leaning that direction.