"Bob" wrote in message
...

I listened to a tech report on the radio a 3 or 4 years ago that told
of an experiment to see how long it would take a completely (pre vista
era) unprotected idle computer on a high speed internet connection to
be infected with something. The average time it took to infect a
computer was four minutes. That alarmed me so that report stayed with
me. I really do not know much about the process of how infections
happen.

There was a lot of network worm activity back then (based on DCOM RPC
exploits). Your firewall likely blocked any incoming exploit code
packets (which you probably weren't susceptible to on Vista anyway).