When you delete a file, it doesn't actually go away--even after you've emptied the Recycle Bin. The actual bits remain written on the drive until some other disk activity writes over them. Even when you format a drive, the files are still there for those who want and know how to read them.
If you want to truly and securely delete a file, or the contents of an entire drive, you need software that will overwrite the space where the file(s) once sat. Fortunately, several free programs can do this.
1. I recommend the File Shredder feature built in Wise Care 365, choose any file or folde