How this happens is: You go to a website and suddenly something flashes on the screen that says one of your programs needs updating. Unfortunately getting update notices like this is false. You could have gotten this because you typed a wrong address or there is a temporary problem with that particular site.
Clicking on a link like that will install, ad-ware, spyware or, at worst a virus. So be careful. Understand that most of the wanted updates will come from a notice that originates from the clock on your computer. If you suspect that something does need to be updated, don't take the popup from the internet but go directly to the manufacturer's website to download.