You don't actually delete anything. When you select delete, although the
file pops into the recycle bin, the actually 'area' that the file takes up
is simply marked as 'free space'. In other words, until that space is
overwritten the file is still there and, using the correct software, can
still be accessed. To permanently delete a file you need to have the space
overwritten. You could try the third party freeware application called
Eraser (www.heidi.ie/eraser)