To open a URL from a .NET application, many sites (including on StackOverflow) cite this example:
Process.Start(\"http://www.google.com/\");
<
You may try to specify the Process filename "explorer.exe" explicitly, like suggested in the following thread:
http://social.msdn.microsoft.com/Forums/nl-BE/toolsforwinapps/thread/e051a102-469e-4ede-882c-c2c89377652a
var startInfo = new ProcessStartInfo("explorer.exe", url);
Process.Start(startInfo);