APM 3.1 Not working

i bought this APM 3.1 from banggood.com    http://www.banggood.com/MiniAPM-V3_1-Flight-Controller-With-Neo-6M-GPS-For-Multicopters-p-951861.html

When i plug it in my computer the lights go on, but my computer doesn't recognize the APM : (

please help m

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