Sam,
I have made a macro which uses a user form, where you could type the Username and the Password. If either of them is wrong it gives the user two more chances to get them right until it closes the workbook, but not Excel itself. If he gets them right it opens your welcome page "Navigation", and closes the user form. I have one question: Is "Navigation" a html file in your computer or in the web, or is it another sheet in your Workbook?

Swisse