The final blow was when the built-in microphone port went south.
ASUS tech support gave me the phone number (in Fremont) to call for an RMA, I called, it was painless, after a 10-minute on-hold time, and they sent email with instructions. The instructions said it would take 10 days. That's a long time to be without my main PC, but the seller won't take it back without all the accessories, which would mean tearing the whole machine apart, and I can't do a Fry's instant exchange because they track serial numbers. I may end up getting a new one at Fry's or Microcenter and selling the refurbished one on eBay.
While I'm at it, I'll look for a bigger case, too.