allenb~ is spot on

AV products are generally not very good with trojans, and Norton is very mediocre.

Moosoft is good, for a nice free AT specialist:

http://www.emisoft.com/en/software/free/

A-squared

Also:

http://www.ewido.net/en/

The interactive bit only works for the 14 day trial, but the on demand scanner can be updated and used for free after that.



EDIT: Run these two and your AV in SAFE MODE