Does anyone else that uses Norton Internet Security 2012 notice that after it has been installed for about a week or so, that internet browsing slows down considerably? It seems that shortly after install I don't notice any slowdown. But I have had it installed for about a week or so and now it takes several extra seconds to open a browser and then browsing is slow. If I disable the Norton add-ons in Firefox and restart the browser it returns to normal speed. Just me, or are others seeing this also?