Bearshrum
You know, you are lucky because you downloaded some rubbish designed to constantly serve you with annoying adverts, which you easily got rid off.
You could have just as easily downloaded something designed to insinuate its way into the heart of your computer and silently steal your bank and/or credit card details. And the only way to get rid of something like that, if you know it's on your machine, is by reformatting your hard drive.
The Internet now is a very dangerous place for the unwary, just be thankful that you caught the "mildest" of the million plus dangers that are out there.
UK Bob
PS. Check out this article -
Personal Computer Security: Using Uncommon Sense | ZDNet