Antivirus Recommendation

I recommend Norton by Symantec or McAfee Antivirus products.  It gives you the piece of mind of a team of professionals working to protect your PC.  They find old viruses and have a good support network.

AVG is good for free anti-virus protection. Also Microsoft Security Essentials works well, and MSE is now available for free from Microsoft. I have not tried AVG or MSE, but they are running OK on friend's PCs.