All the friends and family member who I've seen get infected recently have been hit by those fake anti virus products claiming that their machine was infected and tricking them into installing them. Or they've been tricked into installing a trojan that was pretending to be an update for Windows or IE (even the ones that aren't using IE).

All of them had either MSE or AVG installed, it is extremely annoying that they make no effort to target this malware.

This whole area is a pain in the arse. My Mum is a new computer user. When she Skypes me and asks if a particular message saying an update is available for something it basically impossible for me to tell her whether it is legit or not without viewing her screen.