Network crashed sometime yesterday; intermittent Internet access followed by complete shutdown on all systems. Man, what a pain. Checked all systems, of course, and they all were fine - just incommunicado. Great. So Comcast upgraded a few weeks ago here, and the modem couldn't handle that, so it had to be replaced. Maybe that was the problem.
Nope, didn't seem to be. So, let's check the router (Cisco/Linksys EA-2700, their top-rung). Unbelievable. Yep, it's fried. Trail tip: don't buy the 2700. You get better results with the 2500, which is also A through N compatible and features dual-band for less interference.
After swapping out the 2700 and setting up the 2500 (which, by the way, is actually easier than setting up the 2700), everyone was back online with high-speed access. Even the printers were easier to re-set.
Trail tip #2: when wireless access starts screwing up on a 2700, wired ethernet won't work either. The ethernet started failing within hours after the wireless went down.
All in all, the 2700 is crapola - six months old, and nothing but a pain the whole time. You expect better from Cisco.