HTTP Error 404 - File or directory not found. Internet Information Services (IIS)

Try again

Just try to load this before, RSPB community not responding!! OK on each of my pages, once logged in, all my navigation icons are missing. There are hidden icons, but when you click on any of them the above message comes up on a new page, Also telling me that the page(s) do not exist. What is going on, this used to be a brilliant web site, now I am having extreme difficulties navigating the pages

 

TB