Adware and Spyware can cause many problems on your computer.
Your computer will run slower and you will get uncontrollable popups.
When you visit sites on the internet, scripts are downloaded to your
computer without your knowledge or concent. They track where you go
and what types of things you look at so they can try to sell you things
that you might want. They then go out to their home base to retrieve ads
that popup in your face to try to get you to buy.

Having these things on your computer will slow your system down by
taking up memory and processing power.