Private Declare Function RegCreateKey Lib "advapi32.dll" _
Alias "RegCreateKeyA" (ByVal lngRootKey As Integer, _
ByVal lpSubKey As String, _
ByRef phkResult As Integer) As Integer
 
Private Declare Function RegSetValueEx Lib "advapi32.dll" _
Alias "RegSetValueExA" (ByVal lngRootKey As Integer, _
ByVal lpValueName As String, ByVal Reserved As Integer, _
ByVal dwType As Integer, _
ByRef lpData As String, _
ByVal cbData As Integer) As Integer

Public Sub regCreate_Key_Value(ByVal lngRootKey As Integer, _
ByVal strRegKeyPath As String, _
ByVal strRegSubKey As String, _
ByRef varRegData As Object)
        Dim lngKeyHandle As Integer
        Dim lngDataType As Integer
        Dim lngKeyValue As Integer
        Dim strKeyValue As String
        lngDataType = REG_SZ
        m_lngRetVal = RegCreateKey(lngRootKey, strRegKeyPath, lngKeyHandle)
        strKeyValue = CStr(varRegData)
        m_lngRetVal = RegSetValueEx(lngKeyHandle, strRegSubKey, 0, lngDataType, _
          strKeyValue, Len(strKeyValue))
        m_lngRetVal = RegCloseKey(lngKeyHandle)
End Sub

Private Sub okButton_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles okButton.Click
        regCreate_A_Key(HKEY_CLASSES_ROOT, "call")
        regCreate_Key_Value(HKEY_CLASSES_ROOT, "call", "", "URL:call Protocol")
        regCreate_Key_Value(HKEY_CLASSES_ROOT, "call", "URL Protocol", "")
        Windows.Forms.Application.Exit()
    End Sub