|It is not free but I have used Webroot Secure Anywhere (Antivirus, not suite) on my computers at home for may years and it does not slow anything down in anyway I can tell. It is light on system resources and does not have any annoying pop ups. It simply works. They may have a free trial on their site (I have not looked lately) so you see how it works.|
Please start with above cleaners first and report back results and copy/paste logs back for review.
You have to be a little bit crazy to keep you from going insane.