If you’ve been hacked or had your server crash and lost your website with no backup there may still be hope. Be warned, it will mean manual labor and sourcing your pages from one of two sources.
If you search for your website using prefix cache: you may find what you’ve lost providing Google has refreshed it’s cache for your site recently. If you are indexed by Google, they will have at least one cache archive for you. Try it now, log onto Google and search for cache:yoursite.com
This is also a cache repository but is less likely to be as current as Google’s cache repository. The Wayback Machine is an internet archive of “popular websites” so there is no guarantee your site is on the list. All you need to do is paste your website’s url here http://archive.org/web/