. . is a pretty sophisticated computer user - but there are teens in the house.

One thing the infectors have been doing lately is breaking into the servers of perfectly legitimate Web sites and distributing their stuff from there for as long as it takes for the admin to realize s/he's got a problem.

Many other vectors are being exploited as well. Everyone I've had to clean up lately was running an up-to-date virus program - mostly AVG (paid) but others as well.