I have a home network w/ 2 workstations attached. One has virus and spyware protection and one does not. The xp workstation w/out protection became infected w/ some malware/viruses/trojans. I took it to a local shop to get it cleaned. They asked if I had a network at home and said the viruses came from a pc on my home network, they gave me the specific computer name of the other pc in my house. I sort of questioned them on that b/c the pc they said it came from is updated and scanned daily w/ its virus protection and nothing is ever reported. I even made sure it was up to date and did another full scan when I got back home and still nothing was reported. I am using the latest AVG virus and spyware software. How can could they tell if the virus came from that computer or if it came off the internet?