Yes, I understand that you have a problem, but you are making it the reader's problem, instead of yours to resolve.
I'm not trying to be combatative here, but this is microsoft.com... surely you should provide the appropriate work-around (sniff the browser/platform/version if needs be) to give the user a experience that emulates the intention as closely as possible.
There are plenty of ASP.NET menu solutions that work just fine accross multiple platforms... e.g. Telerik's menus work with Safari.
http://demos.telerik.com/aspnet/prometheus/Menu/Examples/MultiColumnMenu/DefaultCS.aspxAs for the silverlight thing... again... this is not the reader's problem, it's microsoft's problem to provide them with an experience that makes them want to use the site... the browser/plaform doesn't correctly support silverlight... ok, detect it and provide a flash option... you don't have flash... ok, detect it and provide a base html option.
You can't just effectively tell all Webkit/Opera users that the need to use IE or FireFox with Sliverlight, to access the main site at Microsoft.
Please accept as constructive criticism, not intended to be a personal attack.