Fix WordPress Multisite custom permalink 404 error

I have a WordPress Multisite running on version 3.4.2. Recently I moved my site from sharing hosting to dedicated Windows server. As I have no knowledge on coding and server stuff, so I hired a freelancer to do the work for me. The site was running great until I found Chinese permalink and tags give 404 error on Windows IIS. So I ask my freelancer to fix it, but unfortunately he has messed up my site permalink. Before that, I was using Custom Structure with "/%postname%.html ", and my WP site is hold under a "/blog" folder, so the permalink structure should be: [login to view URL] Right now, the freelancer has messed up the permalink and changed the Custom Structure to " /blog/blog/ " and it gives 404 error on every links: [login to view URL] Now my site only works with the Default permalink structure: [login to view URL] Your Job is to fix 404 errors and revert the link structure back to [login to view URL] (/%postname%.html) If you are able to the fix Chinese permalink and tags problem is a plus. You have to expertise in WordPress URL rules, Windows Server IIS and has experience of working on WordPress Multisite. Thanks You!