Setting the excel macro for getting disk space using the API call.

I need the easiest way of setting the API call in excel macro for getting disk space. I do not wish to set the declarations and module because it is a long statement. I think, this can be done through the copying and pasting the ready made file for the declaration. I have the access to Visual Basic. Which is the name of that file and where can I get it, if there is any site? Thank you.
