Put something like this in the form that will have the command button:
Private Sub [your button name]_Click()
DoCmd.OpenForm "[your dialog form's name]", , , , , acDialog
End Sub
Put something like this in the dialog form:
Private Sub Form_Load()
DoCmd.MoveSize 1444, 2000, 3000, 3000
End Sub
Note that:
Numbers after 'MoveSize' represent
, [Down], [Width], [Hight]
Units for MoveSize are twips, 1/1440 of an inch, 1/20 of a point
Later,
Philo