problem solved
Called Microsoft support - they were able to find & fix the problem without a reinstall, and run a program to remove the four registry entries I was incorrectly encouraged to install early on in this thread. They're calling back tomorrow to make sure the OS is running smoothly.
What caused my Windows Firewall and Windows Security Center to shut down (and what prevented them from starting again) were two trojans:
Trojan:Win64/Sirefef
Trojan:Win64/Sirefef.AA
I'd caution Adblock/Adblock Lite users: the plugin may stop popups, but instead the ads may flip over web pages within Firefox windows. One of them flipped over a page I had open--clicking on it by accident brought in the trojan.
The free Microsoft Safety Scanner I downloaded a few days ago said it detected 5 problems, but listed only 4 as being removed, including those two. The Microsoft rep (who, despite less-than-perfect English, was very thorough & smart) saw this on my post & said this was the problem - she said these trojans can attach to any program on the computer. While an antivirus/antimalware program may say they've been removed, remnants can remain. She said they need to be carefully deleted since it's possible a program may be deleted along with it.
I tried to call Kaspersky & have them simply look at the info I posted here to determine whether or not they could fix the problem--if they thought they could, I'd have signed on for a year. But one tech there replied to my email (similar to my first post here) by telling me what I needed to do to remove programs to install Comodo. When I pointed out this wasn't the question I asked, she replied a day later by just saying that Kaspersky and Defender wouldn't run simultaneously, ignoring the question of whether or not they could solve the root problem. When I called them, the phone rep who looked at my ReportMaker report said there was nothing that appeared to be a problem -- when I asked for a supervisor to review it, I was told only customers could talk to them (never mind that I was figuring out if I should become one).
Once the Microsoft rep told me she solved 6 of 6 similar cases without requiring a reinstall, I figured it was worth the risk, She went through folder by folder with a Microsoft program and removed the trojans from several folders. Also ran the Kaspersky TDSS Killer and ESET online scanner (which found an additional "variant of Win32/Adware.Yontoo.B application," but she said that wasn't a major issue).
I really do appreciate Karl's help. I'd also encourage any board members to question the reasoning behind any advice, and for those giving it not to take offense when someone questions it (as long as it's done politely). Both approaches will foster an environment here that's more fail safe.
Let me explain: after my initial post, I was directed to a Microsoft site with an answer that advised making registry changes--yet when I posted here that I didn't have the symptoms that fit the problem on that page, I was encouraged to make the registry changes anyway by the same "power user". Ultimately it was my fault for taking the advice--If I'd been more questioning, I wouldn't have gone along with it, and maybe without the resulting complications I would've been able to solve it with Karl or someone else for free.
Thanks again to everyone who helps on this board & runs it!
