Now here's the thing. Maybe Norton clears it off but another trojan reinstalls it and the cycle repeats. Norton is not all seeing so you learn to use a few scanners to see what all has taken up residence in your PC.
Grif notes what I use at http://www.cnet.com/forums/discussions/how-to-remove-pup-option-603542/#post-f742c795-5881-433b-a29b-6d758efe5cd3

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