Dropdown Menu

I have created switcboard. One of my Buttons are linked to a Macro that opens a Query with a Criteria option whereby they have to put The Employee Code in to view the information they require.
What I want to do is to (instead of seeing Option to ENTER EMPLOYEE CODE
I want a List of All Employee codes to be displayed and then when they select a specific Employee code it opens the form

How do I get that List displayed as a Pop up and then have it open the form on the Selection of the correct Employee Code. ( Remember this is now suppose to happen BEFORE the form opens with the selected Employee Info -

re: Dropdown Menu

It sounds like you would need to have the button open up a separate form that contains the drop down list (Combo Box).

Also, maybe you could put a combo box on the switchboard instead of the button?
I've never tried that, but maybe one of the experts (which I am not) on this forum could tell you if that would work.