If you want to have file sharing through a browser, why not use an FTP server (I thought IIS came with one, but I'm not sure 'cause I use Apache on Windows as well as Linux for my http server and I don't use an FTP server on Windows for security reasons.)

If, on the other hand, you don't want file sharing through ANY way at all, use a firewall such as Zone Alarm on High security settings (default for internet zone)... this should block access to ports 135,137-9 and 445... all of which have some role in Windows File & Printer Sharing (NetBIOS)