Hi everyone,
Like Linda mentionned, I have a wireless rooter (encrypted), that puts another wall for anything that would try to enter your computer.
I use AVG (
AVG Anti-Virus and Internet Security - Welcome) and since I use this program (2 years), I have never got a virus yet. It's probably not well known but when I installed it 2 years ago, I had scanned with Norton, everything was clean, then I uninstall Norton to install AVG and it has detected few virus!
However, it's not free but I don't mind to pay 30 or 40 dollars for a reliable anti-virus program that I put on my business expenses (income taxes) :-)
Good luck!