Confirmation Mail to activate an account in the Membership table

Hi,
 
I work with an ASP.NET application and the standard Membership ASP.NET database to register user.
Could it be possible to explain or to give examples how to program the system to work with a confirmation mail so that the user need to click on the link to activate his account?
I would like to do this to avoid SPAMMERS
 
Kind regards,
 
Philip
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