I know that just deleting data does not totally remove the data from my hard
drive. My question is, is there any software to remove this data permanently,
as I am giving my computer to charity. Thank you for any suggestions.
Yes and no. It depends on what you mean by "permanently."
1 When you delete a file, it normally goes into the recycle bin. That
"removes" it in one sense, but it can be retrieved from the recycle
bin, if the bin hasn't been emptied.
2. Once you empty the recycle bin, you can no longer retrieve files
from it. However a deleted file is still on the disk --just the space
that it used is now marked as available. There exist many different
undelete programs that can still recover the file, until the space is
rewritten.
3. Once it's gone from the recycle bin, you can make the file much
more difficult to recover by using one of the many available programs
that overwrite deleted files multiple times. Google will get you
several choices.
4. Even if the space has been overwritten multiple times, there are
sophisticated (and usually very expensive) data recovery techniques
that can still, at least sometimes, find remnants of the deleted file
and recover it.
5. Because of that last point, the US government does not rely on any
software techniques when getting rid of really sensitive data, but
physically melts the drive in a furnace.
Still, for the enormous majority of people, that overwriting is
certainly sufficient.