Thanks for the "clear the cache" tip. I set Firefox to do this every time I exit all Firefox windows.
But I opened Internet Explorer and cleared that cache, too. That helped quite a bit.
Then I did a Search on my computer for all files with tmp extensions and got rid of advertising/cookies junk. I find I need to do this a few times a month.
Comcast cable internet uses McAfee. Appears to be useless.
Sending emails from yahoo is still funky. I can send a few, then suddenly I can't send at all.
Arggggh!