Mystery Music through WiFi Card?

Whenever I get my email client up and running on a notebook with a
WiFi card the computer plays a brief tune. The notebook connects to
the internet via a router which is wire connected to my desktop. The
Site Survey on the notebook notes only one other router nearby which
clocks in at about a 9.

Is someone hitching a ride throug my WiFi card? Or playing a game
with it? Is there anything to worry about? The notebook does lock up
sometimes when I am in the middle of doing work online. I tried
turning on the firewall of the notebook, but that blocked access to my
own router.

TIA for any helpful suggestions.

"Tom"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~
Human speech is like a cracked tin kettle, on which
we hammer out tunes to make bears dance when we long
to move the stars. Flaubert. Madame Bovary.