How to find a specific hidden file?

Hey guys, I'm rather new on here so I'm kind of a noob at this stuff but I need help. When my little sister was visiting over here, she used my MacBook Pro 15-Inch (Mid 2009 model) for the couple weeks she was visiting. While she was here, she installed an array of software on here including one unusual one I've read could cause trouble to Macs. Every time I use Google Chrome (my default browser), a warning tab says "Could not access the Extension "Nielsen NetSight" and now my sound to my speakers on here is always changed every time I start my computer to some source called "Nielsen Audio". I looked into it and it's a digital voice site which offers money to people who install the software (Nielsen Digital Voice - Home) .. I looked in finder and searched all my hidden files and I can't find it.. Can someone please help me locate hidden files such as that? Has someone had problems with this (Nielsen) software before?? It's making my Mac really sluggish and causing problems. Thanks.

What happens when you do a spotlight search for "nielson" and "insight"