Pop up VB in excel 2010

Hey guys,

I have a large excel file with tons of information about my employees. I need a way to have a pop up to remind 3 months in advanced for when their visa are about to expire or when I have to set up a flight.

I would need a formula or a code in VB that would fetch the right information and notify me when the due-dates are close. Ive seen many codes but none have worked so far.

thanks =)