Steve wrote:

Still mostly good, but... Today I was on Facebook and the page would
refresh itself for no reason. Could be a Facebook problem, but...
Tonight I was on Facebook and trying to write a long answer to something
on a group and it would refresh, making my writing disappear. I had to
open notepad and type it there. Even notepad would jump, blink out and
come back. When it did this, it would insert the date into what I was
typing. I got it done and I copied it into Facebook.
As I'm typing this, here with Thunderbird, everything is normal. While I
was fighting with Facebook, a message popped up saying a "security and
stability" update had been downloaded and I needed to restart. I'll now
shut off the computer and go to bed. Tomorrow, I'll start it up and it
will finish the install. Now I'll wait to see if my computer becomes a
mess again, or, do I dare to hope it will fix things this time? I'll let
you know.

Have you reviewed the processes listed in Task Manager's Processes tab
to ensure there are no rogue programs running?

When was the last time you update your anti-virus software (hopefully
you are using something a hell of a lot better than Microsoft's) and ran
a full scan?

Oh, and you only have *ONE* anti-malware program active, right? You can
install multiple anti-malware programs but only ONE should be active
(running real-time) while the others are configured to NOT load and used
only for manually-instigated scans. One active, the rest passive. For
example, I have avast AV free active while I degraded MalwareBytes
AntiMalware (MBAM) to only a manual scanner by disabling all its startup
options. Although MBAM comes as a trial with everything enabled, I
don't want it active along with Avast plus I'm not paying for it, so it
will cripple itself when the trial expires, anyway. MBAM is good for
finding what got in but Avast is better to keep it out in the first
place to eliminate having to perform eradication. MBAM is a fly
swatter. Avast closes the door to keep out the flies.

You never did respond as to whether or not you have tested by booting
Windows into its safe mode (with networking enabled).