Get Nod32 I think it's called. Or get some kind of freeware anti-virus. Unless you have a mac (I'll get to why) then you need to have some kind of anti-virus and preferably a firewall. If you have a mac, than you really don't need to worry about it since you have to TRY to get a virus on a mac.
yes, another guy that has Nod32, yes get Nod32, its one of the best(in my opinion) anti-virus out there, and blocks and incoming virus sites(pop ups with virus)