Im not saying they can stop the spread of future stuff, but they can sure as hell slow it down. Install a firewall, do your updates, dont click on stupid pop ups, dont open emails from people you dont know, especially attachments, have an antivirus installed on your computer and keep it updated, do all updates for both your OS and other things like firmware updates for hardware firewalls, dont use products (suh as IE) with tons of known holes when there are alternitives (like firefox, opera) keep your software uptodate (dont be using IE 5.0 etc.) use programs like adaware so if you do get some it gets rid of it for you.

there are alot of simple things a person can do to prevent the spread of virusis. they can protect them selves by using basic told (alot of which are free). its not hard. like I said, you cannot stop the spread of virusis, but you can slow it down, and you can protect yourself. every unprotectd computer is just another potential launch point for that virus to spread. By protecting yourself you are in effect protecting others.