Code:
Public Declare Function ShellExecute _
 Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As _
Long, ByVal lpOperation As String, ByVal lpFile As String, _
ByVal lpParameters As String, ByVal lpDirectory As String, _
ByVal nShowCmd As Long) As Long

Public Const SW_SHOWNORMAL = 1


Private Sub Dir1_Change()
    File1.Path = Dir1.Path
End Sub

Private Sub File1_DblClick()

    If Len(Dir1.Path) <= 3 Then d = Dir1.Path & File1.filename
    If Len(Dir1.Path) > 3 Then d = Dir1.Path & "\" & File1.filename
    ShellExecute Me.hwnd, vbNullString, d, vbNullString, "c:\", SW_SHOWNORMAL

End Sub