Signs of a Possible Spyware Infection
You will notice your computer is slower than you expect it should be. Sometimes you'll have toolbars or programs that you don't remember installing, icons in the System Tray by the clock that haven't been there before. You may be getting Popups even when your browser isn't open, or as soon as your browser opens you get Popups. Sometimes spyware will change your home page. All of these are signs you have spyware on your computer. There are many more, but these are very common.
You should not click on popups while surfing the web for ads but especially don't click on what appears as speed enhancers, spyware removers, security ads...these are just spyware/malware or viruses.