[CoMaToSe]

I have a strange program that seems to have inserted itself on my computer. on any given web page, seemingly random words are underlined, and are linked to a wealth of information about online dating, free pornography, gambling, and crappy job opportunities. When highlighted, a small text lights up, explaining this to me, then adding that the information is supplied to me not through the website I am currently viewing, but something called TopText/EARN. What is it, and how do I rid my computer of it, without a lengthy run of Norton Antivirus?