Malwarebytes

This is a great piece of software.  It seeks and destroys malicious software on our computers.  The free edition scans, detects and quarantines any threats found when run manually.  The paid version continuously scans your system and does the same when threats are found.  If you are like us, and prefer the no cost version, there is a way to turn off the ads asking you to purchase the product,

To do so, open Malwarebytes, click on Settings, (lower left), and then click on My Account.  At the bottom click to deactivate the trial version.  Another popup will show near the clock and you want to select the second option.

Now your program will run free of ads asking you to buy it.