Well, if you don't have money or don't want to pay for any apps for security. Then I suggest you download... Sygate Personal Firewall for your Firewall obvisouly. AVG Free Edition for your anti-virus scanner. And for spyware Ad-aware SE Personal an SpyBot - Search and Destroy.
http://www.pcworld.com/downloads/fil...id,8132,00.asp
http://www.pcworld.com/downloads/fil...d,15202,00.asp
http://www.pcworld.com/downloads/fil...id,7423,00.asp
http://www.pcworld.com/downloads/fil...d,22262,00.asp

And the programs can be found on PcWorld.com if the links above do not work.