Opening the Internet Browser Programmatically

You're incorrect. Explorer is Windows Explorer, not Internet Explorer. Try this:

System.Diagnostics.Process.Start("explorer");

then this:

System.Diagnostics.Process.Start("iexplore.exe", "http://www.codeproject.com");

and this:

System.Diagnostics.Process.Start("winword.exe", "http://www.codeproject.com");

So, just because you got to the intended web site doesn't mean you used the right application.