How to remove/uninstall downloadnsave ads from my internet/computer?

[Jake]

Okay, yesterday I typed in faceboook.com instead of facebook.com and something downloaded on my computer - I couldn't cancel it or anything. And then later I noticed that I have ads from DownloadNSave that pop up on the top or sides of websites. And they are really annoying cause they pop up on every website I go on (for instance if I try to watch a video on youtube it will pop up above the video and it will pause the video and have an ad before the video starts - which then results in the video loading slower). So I want to remove them but I cannot find anyway to remove them. I have looked in my control panel in the programs section and in my add-on section to get rid of this thing. I have looked on many websites for help but I can't find a way to get rid of it. Can someone help me get rid of this? I have windows vista for a computer. Thanks.