<p>[avast</a>! - Download antivirus software for spyware and virus protection](<a href=“http://www.avast.com/]avast”>http://www.avast.com/)</p>
<p>Avast is free. I use Avast and TrendMicro (from Rice) on my desktop that is used as a server as well. </p>
<p>Id install avast until you get to Rice. Running w/o an antivirus system is dangerous. Further if your PC is infected at ALL when in comes in, it can be quarantined from the network.</p>
<p>AVG also has a pretty good free anti-virus system</p>