I'll give you the facts of what happened. I don't know if any of them are related, but here they are.
An agent at ATT told me that the Spam Advisory email was fake. Fortunately, I had known better than to click on any of the links. I sent him a copy while we were on the phone and he said it wasn't anything like they sent. Also, the account number was wrong. He sounded knowledgable and confident and I was happy to get someone like that at ATT customer service -- for once. He suggested I change my password, so I did.
Then I switched from Panda antivirus to Avast on the Dell. I scanned the hard drive with Avast, Malwarebytes, and the Dec 2015 dowload of a Microsoft anti-malware tool. All found nothing. But Avast reported that my Netgear router had been hacked, infected, and had various vulnuerabilities. I updated the firmware on the router and changed the password. Avast no longer reported problems.
The next day the phone line went out. No dial tone, so no internet obviously. We'd had a ice storm the night before, and I don't know if that was the cause. ATT chose to send out a repairman, but he didn't get here the day he was supposed to. Instead, the phone line magically healed itself and I've been on the internet ever since.
Following the advice of Joe Kissell in his e-book Take Control of Mac Security, I changed the DNS servers in my router settings to a couple Open DNS numbers he recommended in his book. In his old book, I read about the "hidden firewall" in OS X and contemplated whether to use it.
I haven't noticed any odd behavior. I don't know if my Mac or the Dell or the iPad were hacked or harmed. Data seems intact.
Hard for me to believe that someone or some-bot hacked my router, esp. considering the security I already had, including a good password generated by 1Password.
