[help]Full Screen

    Private Declare Function FindWindow Lib "user32" Alias _
    "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName _
    As String) As Long

    Private Declare Function SetWindowPos Lib "user32" _
    (ByVal hwnd As Long, ByVal hWndInsertAfter As Long, _
    ByVal x As Long, ByVal y As Long, ByVal cx As Long, _
    ByVal cy As Long, ByVal wFlags As Long) As Long

    Private Const SWP_HIDEWINDOW = &H80
    Private Const SWP_SHOWWINDOW = &H40

    Public Function HideTaskBar() As Boolean
        Dim lRet As Long
        lRet = FindWindow("Shell_traywnd", "")
        If lRet > 0 Then
            lRet = SetWindowPos(lRet, 0, 0, 0, 0, 0, SWP_HIDEWINDOW)
            HideTaskBar = lRet > 0
        End If
    End Function

    Public Function ShowTaskBar() As Boolean
        Dim lRet As Long
        lRet = FindWindow("Shell_traywnd", "")
        If lRet > 0 Then
            lRet = SetWindowPos(lRet, 0, 0, 0, 0, 0, SWP_SHOWWINDOW)
            ShowTaskBar = lRet > 0
        End If
    End Function
Here's an example with 2 buttons.
You can do it with Form1_Load to have the task bar automatically disabled when the app is started
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        ShowTaskBar()
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        HideTaskBar()
    End Sub
End Class