IF your computer is a wireless to the modem or your router then: In the lower right hand corner of screen there should be an icon of stacked bars. This is your wireless connect. Click this, you should see H2g etc and be given the opportunity to Disconnect. Data usage only happens via internet. If windows update is set to auto, there is data usage behind the scenes. Also, if you have any auto backup software like Carbonite, there will be usage there also.
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