Windows Update and malware.
You didn't tell much about your machines so I'll write to scan them with MBAM and stop here.
Bob
Whenever i am switching on my net,its internet LED starts blinking heavily and in my usage shows heavy download and upload value,even though i am doing nothing.i have installed zone alarm but still problem existing.also i have tried tcp view-but i am unable to stop the problem.......can any body have solution for this.......

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic