Windows - Issues Setting Default Browser

Setting your default browser should be a rather simple task in both Windows XP & Vista. Just right-click on the "Start" menu, choose "Properties", click the "Start Menu" tab and "Customize". You are presented with a handy dropdown menu that allows you to choose between the different installed web browsers on your machine. That's all she wrote, right? Well, not if you have installed Opera, or at least the latest Opera Beta (9.50b)...