give this a whirl

add a common dialog control to your first form
Code:
Private Sub FindDB()
Dim dbLocation As String

On Error GoTo Open_Error

With CommonDialog1
    .DialogTitle = "Find database"
    .CancelError = True
    .Flags = cdlOFNFileMustExist
    .InitDir = App.Path
    .Filter = "Microsoft Access Database |*.mdb"
    .ShowOpen
    dbLocation = .FileName
End With

Exit Sub

Open_Error:
    Select Case Err.Number
        Case 1
            Exit Sub
        Case Else
            MsgBox "Error " & Err.Number & ": " & Err.Description, vbCritical
    End Select

End Sub
You might have to change a few things around to fit your program, but that is the basics of it.