Yes additional security is needed, you need an on demand anti virus program. its up to you, there's nod32, norton and AVG. those were my favorite. they never fail me. my security programs AVG 8.0 Professional SUPERAntispyware 4.15.1000 Professional Spyware Blaster (for prevention) Add'l on demand scanner Spybot S&D I feel very safe and secure with AVG 8.0 and SuperAntispyware.