Hmmmm...! Just a thought, do you have firewalls in place on your computers? Coz since you have ADSL you really should have. You never no there may be a Trojon file on your PC.
Check out this this site and frighten yourself into installing Zonealarm at the very least!!
www.grc.com And for zonealarm (which is free by the way!!
)
Zonealarm