In the explorer window, go to View > Show hidden files... Or maybe it was Right-click > View > Show hidden files... Something like that.
Open any explorer window, ie: "My computer" Should be very similiar to: Tools -> Folder Options -> "View" tab -> check/uncheck "Show hidden files or folders" You can then apply that to all folders, or just hit ok to have it apply to just that folder.
As a rule i like to set show hidden files and show system file along with show file extensions. Well cant be to careful.