I've now stripped down my entire machine to a motherboard, naked with its guts hanging out, connected minimally to a power supply and a speaker.  According to ASUS this is supposed to be able to post and give me a "no CPU" or "no memory" error.  I can't even get that.  I'm so frustrated.  I guess this is why professionals deal with this sort of stuff usually.  Well, at least now I can focus my ire on the motherboard.  I will naively attempt to get tech support from ASUS on it tomorrow but I'm expecting to have to get a new one...