Yep as above I'd also recommend Microsoft Security Essentials - it's low on resources, doesn't nag you and its clear on what needs done. It has an icon in the task bar which is green when it's happy, orange when it needs some attention (definition update or a routine scan) and red if it needs immediate attention and when you open it up the options are very straightforward. I support the enterprise version (installed on around a thousand machines) and it's detection/removal rate is very good, it doesn't catch absolutely everything but then nor does any AV product I've used and it's managed to stop considerably more than the previous client used.
I don't agree with having multiple AV clients on the same machine as they can interfere with each other and significantly increase the number of false positives because each client has its own rules for detecting virus code which means another AV product can find these rules as malware because they match the pattern for a virus. If a machine is infected and the main client has failed to stop it, I'd go to a more specialist product specifically for killing it rather than running another general AV product. Pulling the wire out of the modem is a bad idea, you're not guaranteed a new IP address every time (because the DHCP lease is longer) and IP addresses will be targeted uniformly, it's unlikely someone is going after you for your specific IP address unless someone has a grudge for you or you're hosting something behind the router. If that type of issue is a concern then the better approach is to upgrade to a router that can better handle the rogue traffic. Worse yet though is that if you keep pulling the cable on the modem, your service provider will register the frequent disconnects and may start lowering your line speed to try and stop the disconnects because it will look like the sync speed is too high for the line particularly if you're on an ADSL max type product.
John
