I'd read http://www.experts-exchange.com/Security/Q_20844585.html and check with the noted tools to be sure no pest has found its way onto your machine
I noticed the other day when transfering some of my Mp3's that some of the file names appeared wierd. When I'd cut/paste a file say with the name of "HappyBirthday.mp3" some other wierd hidden files with the extensions"desktop.ini" or "albumart.jpg" would also move. I'd search for these files but I could never find them. Is it possible that there are other files embedded within my Mp3 files? Is this something that I should worry about?