I use both Norton and AVG when I feel the need to check my system. I have yet to be infected by a virus on my main machine. Although I have had computers other than my main machine infected because most of those are sort of expendable and I tend to be careless with them. A mildly amusing story was when a company that I was working for had just had a new server built for them. I was 17-18 at the time and I was unofficially running my own servers (PWS and Tomcat and FTP) on a Windows 98 machine for some development that I was doing. So the lead "computer guy" that built the server was showing me, a secretary, and a few others the new server and we were oohing and ahhing over the multiple GHz processors and multi gigabytes of RAM. It was running NT Server 4.0 and IIS 4 and some mail server. So I opened the task manager to see the graphs of the multiple processors and it takes forever to load. So I'm like what's going on here. Then the secretary pipes up "oh yeah its been running really slow." So I looked at the processes and this one process was taking up all the CPUs power. So at this point no one really knows that something was wrong but I kept digging and found that this thing was writing thousands of 0 byte files a second. So I asked if the guy had patched the machine. "Oh yes that's the first thing we did" So to make a long story short I went online and searched for the process and symptoms that I had found and discovered that the computer was infected with a derivative of the Code Red worm. At this point I'm thinking all is lost my little server is done for and I hope it wasn't my machine that infected the real one. But after checking my machine I determined that I wasn't affected by anything. Well it turns out that these guys connected it to a network that was assigned ips which were the same as their static internet ips for about an hour just to test network connectivity and before they patched it and it was during this short window that it was infected. So the funny thing was my horribly insecure Win98 PWS combination was clean and the "Enterprise" server was down in less than an hour. Just luck I guess.