Evitar que se ejecute un .exe

[5v5]

hola de nuevo...Miren encontre este codigo que crea un mutex (creo)..ese es el problema....no lo entiendo.....(soy novato)......me lo podrian explicar un poquito, para saber lo que hace ya que si solo lo uso sin saber su logica jamas voy a progresar...

Private Declare Function CreateMutex Lib "kernel32" Alias _
"CreateMutexA" (lpMutexAttributes As SECURITY_ATTRIBUTES, _
ByVal bInitialOwner As Long, ByVal lpName As String) As Long

Private Type SECURITY_ATTRIBUTES
nLength As Long
lpSecurityDescriptor As Long
bInheritHandle As Long
End Type

Private Const ERROR_ALREADY_EXISTS = 183&

Public Function InIDE() As Boolean
Debug.Assert Not TestIDE(InIDE)
End Function

Private Function TestIDE(Test As Boolean) As Boolean
Test = True
End Function

Public Function MutexCreate(sName As String) As Boolean
Dim sa As SECURITY_ATTRIBUTES

If Not InIDE Then
sa.bInheritHandle = 1
sa.lpSecurityDescriptor = 0
sa.nLength = Len(sa)

Call CreateMutex(sa, 1, sName)

MutexCreate = (Err.LastDllError <> ERROR_ALREADY_EXISTS)
Else
MutexCreate = True
End If
End Function

Private Sub Form_Load()
If MutexCreate(App.Title) Then
'Continue execution...
Else
MsgBox "Already active!"
End If

End Sub


Bueno gracias por su atencion