Set maximum forms can be opened (the exe file can be opened 4 times only)

How can I set Maximum forms (exe file) can be opened

(I want to set the exe file can be opened 4 times Only!)

MessageBox("You have already opened This exe file 4 times";

>Solution :

you can use this one:

Dim instanceCount As Integer = Process.GetProcessesByName("yourexename").Count()
If instanceCount > 4 then
    MessageBox("You have already opened This exe file 4 times")
    Environment.Exit(0)
End If