In regards to actually stopping a virus from being downloaded onto your computer, do all anti-virus programs get the job done the same way? The reason I ask is because I currently use the free program AVG supplies. I got into an arguement with my friend about this. It just seems to me that all programs out there are going to have the same virus definitions to detect virii. It makes no sense why one would protect against more virii than the other. Why would people use the one with less protection?