Automatic email generate

Hi all, need your expert help on this. attached workbook has a coloum for date and expire date. I need a script or something to make the workbook sent automatic emails to 2 or 3 contacts when the date is expired. Can this be done? if yes, how can I trigger it to send mails? (Do i have to open it? or press a button? or excel automatically do this?) and one last thing if there are 2 copies of the work book does both of them sends the emails or only one sends it?

Thanks,
Sanjeeva