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You might get a better answer in the Applications and Mac App Store forum since is relates to what you are asking. Usually you will find a better answer more quickly by posting in the appropriate forum rather than in a forum that is not related to what you are asking. Also it is best practice to provide as much information as possible so you get the most accurate.

What version of Mac OS X are you using?
What version of Windows are you using?
Are the contacts you are talking about the ones stored in %USERPROFILE%\Contacts?
If not what program are the contacts in?
What program do you want them imported into on your Mac?
 
I was going to try to help you if you answered the questions I posted. That is if you still need help.
 
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