I recently had the same problem on my XBMC. It turned out that a windows update had installed “Windows Live ID Assistant” and this somehow messes up SMB shares. if you just go to control panel and remove Windows Live ID Assistant” every thing works again! the only downside is i have had to uninstall it several times as it kept reinstalling itself. This was overcome by going into the windows update manager and hiding the update for windows games….I dont use any windows live stuff though so I dont know if it would hinder someones abitly to use any of those applications. Hope this solves your problem
