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
 
Private Sub List1_Click()
  Dim I As Long
 
  For I = 1 To List1.ListCount
    If List1.Selected(I) Then
      If Check1.Value Then
        ShellExecute hwnd, "open", Winamp, List1.Text
      ElseIf Check2.Value Then
        ShellExecute hwnd, "open", iTunes, List1.Text
      ElseIf Check3.Value Then
        ShellExecute hwnd, "open", MediaPlayer, List1.Text
      End If
  Next I
End Sub