what do you mean by backup
Backup means a copy of your work in a different place, so you can go "back" to it when something happens with your current work.
For VX Ace there are scripts that automatically create backups on playtest.
If you have no backup, then you just learned one of the most important lessons for anyone working on computers - allways backup your work.
You are not the only person who lost work because they didn't make backups - that even happens to professionals (I personally know of an architect's bureau that lost all work on a 80k$ task one day before it was due because they didn't make backups).
Sometimes you can repair part of the project by copying files from an empty project - you need to make a new project, and then copy every file listed as missing from the new project to the damaged one. However this usually only rescues the maps, with the database most likely completely lost. If you want to try that, ask for help for it here in the forum.