Again, from experience, if you use the AV, it'll put files and alter settings all over. If you want AV, go for a proprietary package, e.g. Dr Solomon's.
If I got hold of Norton, I'd use it, cos I know what it's like, but if you don't know the animal....
Not much help I know, but swap it if you can.
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Me, sweat? I'm that cool, it's condensation.