You less likey to get a virus from clicking on the "wrong" webpage or "wrong" e-mail .. but your PC can still get infected via other means .. like the old Blaster worm came in via the RPC port with no user input required.
You're are best getting a good firewall and antivirus system setup on the PC at the very least.
You could also try running Linux with UAE on top, it's a bit tougher than bare Windows.
