An unauthorized download starts ribbon advertisement?

My friend recently downloaded a media player onto my computer and it required something extra that I did not know came with it. I got rid of the media player but I still get (bet never use to until the download) advertisements in the form of ribbons and such on my facebook and my yahoo page and others. Where do I go into my computer to remove this? I mean I asked her why the hell she did it and she replied that it was because I needed a better media player and yeah, it said for some things to work she needed to allow for it to add a few things extra. Aside from a few screaming matches, and scanning my computer for male-ware (which there were and are now removed) I can't for the life of me get rid of this. Help please!