You are pausing the main thread of your winform with that code. That means that basically all processing stops for your app.
Notice that you mentioned timer, but you are pausing the _thread_. Because you mentioned the webbrowser control I'm assuming you are showing some content in there that you have control over.
In that case you will want to use JavaScript (yeah!) and use setTimeout() or setInterval(). Check out :
JavaScript Timing Events[
^]