Pressing Delete and emptying the Recycle Bin removes only the file's entry. The data stays on the disk until something else happens to write over it, and a free recovery app can pull it back months later. SoftOrbits file shredder software does that overwrite on purpose. It writes zeros, random data or a named standard pattern over every byte the file used, and only then removes the entry. On a hard drive, a recovery scan afterwards finds the pattern and nothing else.