This is an update to my post titled "Cox Downloading Speed and Security Suite". Enjoy!
After several calls to Cox and two Cox technicians visiting my residence, my low, downloading speed problem appears to be solved. Calls to Cox did no good except to get technicians dispatched to my residence.
The first technician agreed my downloading speed was dismal, put a pad on the cable input to my modem, and switched my cable connection to another source. I think the pad is an impedance-matching device, but neither technician could adequately explain its function. Nothing the first technician did solved my speed problem. So, he left, saying he would see if any of my neighbors were having problems and would report my slow-speed problem to Cox. I never heard from him or Cox again.
The second technician immediately focused on my modem being the problem. Between technician visits, I noticed bizarre behavior of my downloading speed apparently caused by my modem. After disconnecting power to the modem for a few minutes and then reconnecting it, the downloading speed would shoot to speeds as high as 20-Mbps! Then, the speed would reduce to 1 - 2.x Mbps a few hours later. After a few such tests, the modem wouldn't start (i.e., all LEDs solid on) for 20 to 30 minutes and up to several hours one time. When the modem restarted, the downloading speed shot into double-digit territory. I had asked the first technician to replace my modem with another to see if the modem was the problem, but he refused, saying it was "too complicated". However, the second technician replaced my modem in a few minutes, and my downloading speeds increased immediately and have stayed high ever since. Speeds vary but are typically 8 to 20 Mbps as indicated by testmy.net and Speakeasy. Inasmuch as I'm only paying for 7 or 8 Mbps, depending on the Cox source for that information, I'm now a happy camper.

I suspect my downloading speeds that are much higher than the advertised Preferred-customer speed could be caused in part by the PowerBoost feature Cox has recently implemented. However, the second Cox technician was not familiar enough with that feature to confirm or deny its involvement in my much higher than advertised speeds.
As for my security problem, the test copy of PC-cillin I installed worked well for a month. So, I bought it. I asked why PC-cillin doesn't block ads and pop-ups and was told it does but only if there are threats to the computer. So, I've accepted using Internet Explorer 7's pop-up blocker, which works pretty well, and living with ads, which aren't very annoying to me. Actually, I probably should be looking at ads, for occasionally one benefits me.