I think what DELL was saying is System Restore will not restore data. It resets your OS, drivers, and programs only.
Question is how did you lose that file.
1) If you use the normal delete, it goes to Recycle Bin where it remains available until you clean that out. Sort of a safety net for us hasty or careless types.
2) If you do regular backups, you would have a recent copy of that file. Absolute minimum for backups is 1 week. Better is every 24 hours but that can be difficult unless you set up an automatic procedure.
That said, sorry for your loss but hope you learn from the lesson. Don't disable the Recycle Bin and do regular backups.
Took me a couple of very dear losses before I learned and I still occassionally goof up, but not that often, maybe once a year or so.