How to disable function key F5 in operating system using visual basic

Public Class WinControl
        ' This is the function used in order to block the keyboard and mouse:
        Declare Function BlockInput Lib "User32" _
               (ByVal fBlockIt As Boolean) As Boolean
        ' This function will block the keyboard and mouse untill a window with
        ' the specify caption will appear or the given time in seconds has 
        ' past ( 0 seconds - wait forever).
        ' If the window with the caption appears than the given key is send 
        ' to it and the input block is removed.
        Public Shared Function Wait2Send(ByVal caption As String, _
                  ByVal keys As String, ByVal seconds As Integer)
            ' Indicates if the window with the given caption was found
            Dim success As Boolean = False
            ' Start time of the function
            Dim now As DateTime = DateTime.Now
            ' Begining of keyboard and mouse block
            BlockInput(True)

            While (success = False And (DateTime.Now.Subtract(now).Seconds _
                                                   < seconds Or seconds = 0))
                Try
                    ' Activating the window with desired function
                    ' if the window is not found an exception is thrown.
                    AppActivate(caption)
                    ' Sending desired key stroke to the application window
                    SendKeys.SendWait(keys)
                    ' Indicates the window was found and keys sent
                    success = True
                Catch
                    ' Assuming window was not found and sleep for 100 miliseconds
                    System.Threading.Thread.Sleep(100)
                End Try
            End While
            ' Release the keyboard block
            BlockInput(False)
        End Function
    End Class