I recommend using Malwarebytes to combat these problems. Run once a month (or more frequently if you have teenagers in your house), this program will find and eradicate these programs before the situation becomes serious.

To download MalwareBytes, click HERE to go to the website and click the button that says "Download FREE version" (or similar wording). There is no need to buy a version as the free version will do everything that you want. Of course, should you delight in the results, you could always buy a paid version to support the company that makes it, however, the decision is yours.

I have written some instructions that you can use to facilitate the running of this software the first few times until you get used to it.

They can be found HERE.

Now you too can help keep your PC squeaky clean along with your virus scanner.

NB: This program does NOT replace a virus scanner. You will need to have one of these too.
I recommend McAfee Viruscan Plus. It is available HERE. Look for Viruscan Plus. You don't need the full security suite if you don't want to, the Plus version will suffice.