Windows 7: Blocking Phantom Internet traffic

Hello folks,

I am going to a conference for a week and stupid enough, they do not provide wifi (or even cabled) internet access at the conference venue, so I have decided to use my data plan as and when required. My data plan is capped at 2GB and I do not want to exceed that limit, neither do I want to use up all my month worth of data in just a week.

I noticed that my computer has a lot of phantom internet traffic that I can't figure out i.e. I don't know which applications are responsible for this kind of traffic. For a day, I left my laptop on without me connecting to internet and I saw decent use of bandwidth. I would like to avoid this. I have Zone Alarm Free firewall installed and still I see this traffic.

I wonder if there is any application that scans almost each and every internet connection and allows user to control the traffic. (Actually that is what I thought even Zone Alarm does but it seems to allow some internet connections).

Many thanks in advance.