Here are the steps I just went through (starting with a new workbook):
1. Go into Design Mode on whatever worksheet you want to have the button
(in my case, Sheet1). The design mode button is in on the Visual Basic
toolbar, so if that is not showing, go to View/Toolbars, and select Visual
Basic).
2. Show the Control Toolbox using the same method.
3. Add a Command Button to the worksheet by selecting it in the control
toolbox and then clicking or click-dragging on the worksheet. By default,
mine was named CommandButton1.
4. Right click on the button you just added, and select "View Code". The VB
editor opens up, and automatically adds the button's "Click" event.
5. Type in "Open_Access", which will call the subroutine that I gave you
earlier.
6. In the VB editor, insert a module by selecting Insert/Module. This will
insert a new source code module into the VBA project.
7. Cut and paste the example I gave you into this module, in its entirety.
You will need to change the path and the filename to point to an actual
Access database on your machine.
8. Make sure that Excel has the references it needs to work with Access by
selecting Tools/References... in the Visual Basic editor, and checking the
box for "Microsoft Access 11.0 Object Library", or whatever version you are
running.
8. Hide the control toolbox and exit Design Mode.
9. Save your workbook!
10. Press the button. It should open up Access and the database you
specified.
That's the mechanics for hooking up a button to some VBA source. You can
now modify the source code so that the button does whatever you want it to
do. Hope this helps.