Example Program
This program shows how you can use the Shell function and the GetNumTasks function to execute an MS-DOS program. This program assumes that you have the PKUNZIP program stored in the UTILS directory and that you have previously created a destination directory called DESTDIR on your hard drive. 

Create a new project in Visual Basic. Form1 is created by default. 
Add the following statements to the General Declarations section of Form1: 
Dim ActiveApps As Integer
Private Declare Function GetNumTasks Lib "Kernel" () As Integer

Add a Command Button control to Form1. Command1 is created by default. 
Add the following code to the Click event for Command1: 
Private Sub Command1_Click()
    Dim AppDir As String
    Dim Zip As String
    Dim Y As Integer
    Dim X As Integer
    
    AppDir = "c:\destdir"
    ActiveApps = GetNumTasks()
    
    Zip = "c:\utils\pkunzip " & "c:\destdir\" & "test.zip" & " " & AppDir
    X = Shell(Zip, 2)
    SendKeys "%{enter}EXIT%{ }n"
    
    Do While GetNumTasks() <> ActiveApps
        Y = DoEvents()
    Loop
    MsgBox "Pkunzip is finished", 0, "Demo Program"
    
End Sub

     Private Declare Function GetModuleUsage% Lib "Kernel" _
         (ByVal hModule%)

      Private Function TestFunc(ByVal lVal As Long) As Integer
      'this function is necessary since the value returned by Shell is an
      'unsigned integer and may exceed the limits of a VB integer
         If (lVal And &H8000&) = 0 Then
           TestFunc = lVal And &HFFFF&
         Else
           TestFunc = &H8000 Or (lVal And &H7FFF&)
         End If
      End Function
						
Add the following code to the Form_Click event procedure of Form1:       Sub Form_Click()
        lRet& = Shell("NOTEPAD.EXE")       ' Modify the path as necessary.
        x% = TestFunc(lRet&)
        While GetModuleUsage(x%) > 0    ' Has Shelled program finished?
           z% = DoEvents()              ' If not, yield to Windows.
        Wend
        MsgBox "Shelled application just terminated", 64
      End Sub