Did you really erase all that data from your hard drive?
Selling your PC? How can you be sure the data you erased has really been deleted from the hard drive.
The short answer is you can’t. Simply using the delete key isn’t good enough. All that does is mark the space on the disk as useable again, and on a large hard drive the space may not be used again for a long time. So the data stays largely intact.
This can be useful in the event of accidental deletion of important files. Documents, spreadsheets and images including photographs can be recovered after deletion. Even after a reformat and re-install of Windows.
So if you’re replacing that old PC with a nice shiny new one, the safest option before disposing of it is to replace the hard drive with a new one.