index: Page not found and all views pages are gone, too

After deleting all my files under sites all and replacing them with the backup folder through a ftp client my home page shows "page not found", and the one pages that were views are gone. I also can't delete the views plugin and the main menu, that is still visible on the pages without views contain only menu entries for pages without views. This is how the main page looks like: http://www.ilonareny.com/ and this ist how one of the functioning pages look like: http://www.ilonareny.com/terms-and-conditions . Most of my website was made out of views and the main page, too contained 3 views.
Please help!