Formatted To Mac And Want It Formatted Back To Windows, URGENT!

WD External Drives WD Portable Drives
1

Hi All,

My WD Passport 500gb was formated to my laptop (windows) then i had to use it on my university comps (mac) and it formated to MAC, and now i cant seem to use it or access it all when i try and use it on windows, i dont know how to format back to windows, any help please??