Are you serious???
I just upgraded to 10, and my whole configuration is gone. I spent the past several years perfecting it. Now it does not exist.
Why??
Hmm. Don´t you ever use the backup function, particularly before updating? It is recommended, just in case,
although it shouldn´t be a big problem.
By, "my whole configuration is gone", do you mean you're toolbars have been replaced ? If so, turn off the new toolbars and turn back on your old ones.
i mean that my toolbars are gone, the icons in my lister menus and context menus are gone... it's all gone 
Nothing is gone. It's just turned off in favour of the new default toolbars and menus.
You can turn your old toolbars and menus back on. They're all still there in the list of toolbars.