unloading an non-VB related app

[Hack]

da_silvy asked about the caption of the open window because that is what is used to close another running application (regardless of how it got running). If you know the caption, then use this.

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function PostMessage Lib "user32" Alias "PostMessageA" (ByVal hwnd As Long, ByVal wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
 
Private Const WM_CLOSE = &H10
Private Const WM_QUIT = &H12
 
Private Sub Command1_Click()
Dim CloseIt As Long
CloseIt = FindWindow(vbNullString, "Caption Of Window To Be Closed")
PostMessage CloseIt, WM_CLOSE, CLng(0), CLng(0)
End Sub