How can I completely block a hacker

videogamingtown

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Jan 18, 2012
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I've received 2 phone calls recently from a "hacker" who knew a surprisingly accurate amount of stuff about me, I'm on mobile broadband so it's a 3G wifi dongle I use, it has a built in firewall. On my PC I have bit defender with the firewall on , how is this guy doing this to me? I haven't noticed anything suspicious on my PC and did a virus scan today and it didn't find anything either. What other security can I put up to completely eliminate any chance of them connecting to me?