Emptying the recycle bin isn’t enough. To truly wipe files from an old hard disk, you’ll need to install a program like ‘Darik's Boot and Nuke’ (DBAN). — dpa
If you’re selling or disposing of an old computer, you’ll need to make sure that none of your data is still hidden in the depths of the system and capable of being retrieved.
The important thing to understand is that emptying the recycle bin doesn’t actually delete the data from the hard drive.