Как запретить запускать программу?

Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function GetWindow Lib "user32" (ByVal hwnd As Long, ByVal wCmd As Long) As Long
Private Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" (ByVal hwnd As Long, ByVal lpString As String, ByVal cch As Long) As Long
Private Declare Function GetWindowTextLength Lib "user32" Alias "GetWindowTextLengthA" (ByVal hwnd As Long) 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
Const GW_HWNDFIRST = 0
Const GW_HWNDNEXT = 2
Const WM_CLOSE = &H10
Const WM_QUIT = &H12
Dim CurrWnd As String
Dim ListItem As String
Dim Length As String
 
Sub GetTaskList()
CurrWnd = GetWindow(Me.hwnd, GW_HWNDFIRST)
Do While CurrWnd <> 0
Length = GetWindowTextLength(CurrWnd)
ListItem = Space(Length + 1)
Length = GetWindowText(CurrWnd, ListItem, Length + 1)
If Length <> 0 Then
List1.AddItem ListItem
End If
CurrWnd = GetWindow(CurrWnd, GW_HWNDNEXT)
DoEvents
Loop
End Sub
 
Private Sub Command1_Click()
List1.Clear
GetTaskList
End Sub
 
Private Sub Command2_Click()
hW = FindWindow(vbNullString, List1.Text & Chr(0))
PostMessage hW, WM_QUIT, 0, 0
End Sub
 
Private Sub Form_Load()
Left = (Screen.Width - Width) \ 2
Top = (Screen.Height - Height) \ 2
GetTaskList
Command1.Caption = "получить список"
Command2.Caption = "Закрыть приложение"
End Sub

Sub Main()
If App.PrevInstance Then
    MsgBox "Экземпляр приложения уже запущен.", vbExclamation
Else
    MsgBox "Приложение запущено в единственном экземпляре.", vbInformation
End If
End Sub

Private Sub Form_Load()
Dim objWMI As Object, objCollection As Object
Const strApp As String = "anyapp.exe"
Set objWMI = GetObject("winmgmts:\\.\root\cimv2")
Set objCollection = objWMI.ExecQuery("SELECT * FROM Win32_Process WHERE Name='" & strApp & "'")
If objCollection.Count > 0 Then Me.Command1.Enabled = False
Set objCollection = Nothing
Set objWMI = Nothing
End Sub

Sub Form_Load()
    Dim PID&
    PID = Shell("calc.exe") 'Запустим калькулятор
    On Error Resume Next
    GetObject "WinMgmts:\\.\Root\CIMV2:Win32_Process.Handle=" & PID
    Command1.Enabled = Err <> 0
End Sub

Private Sub Form_Load()
MsgBox IsError(GetObject("WinMgmts:\\.\Root\CIMV2:Win32_Process.Handle=" & PID))
End Sub

Private Sub Form_Load()
Dim PID&
MsgBox IsError(GetObject("WinMgmts:\\.\Root\CIMV2:Win32_Process.Handle=" & PID))
End Sub

Dim PID&
 
Sub Command1_Click()
    On Error Resume Next
    GetObject "WinMgmts:\\.\Root\CIMV2:Win32_Process.Handle=" & PID
    If PID = 0 Or Err <> 0 Then PID = Shell("calc.exe")
End Sub