The primary user has no problems and nor did the second user until yesterday when, returning after a break, Firefox opened with a new tab, no menu bars and no menu button drop-down screen. If I clicked on Alt+menu bar or bookmarks bar, they appeared temporarily. It worked if I typed a url into the search box and I could add bookmarks but they would disappear on shutdown. I have tried a reset through Profile Manager and, in desperation, deleted the user completely. After rebooting the PC and creating a new user, Firefox behaves exactly the same way, except that all the bookmarks have been deleted. The primary user still has no problem with Firefox but it seems there is some basic problem with the addition of a second user. I would greatly appreciate any suggestions.