Complete Clean of Hard drive

As an added bit of assurance read Section 2.2 in this lengthy, technical article.

http://www.fsl.cs.sunysb.edu/docs/secdel/secdel.pdf

Thanks for that Gary, interesting (on the third read, though).
To go back I neede software that would wipe the entire C drive. OS as well as data so the Darik's Nuke was my choice. Have to say it worked very well. I went through the process and then hitched the HD to another computer a tried a Recuver on it. Nothing found!! Very impressive. So this for now will be my preferred software. I feel quite happy about re assuring the donors of the used PC's that their security will not be compromised. I tested this on an old XP machine that was full of rubbish anyway. As an exercise I first ran Macrium Reflect to make a backup of the whole C drive. After the successful clean with Nuke I restored via the Macrium backup. All went well! I then cleaned the drive again and downloaded the ISO for XP so that I could do a clean install. All completed successfully apart from the fact that I thought part of the HD had been lost as it was only showing 39GB of space. Then I realised it was only a 40GB HD anyway, that's how old it is but it is working fine and will help someone get strted I'm sure. So all in all a successful venture so far.
Many thanks for all the help and suggestions!

John, only 3 reads?

The article is a big stinkerthinker, that's for sure.

Aside from Government agencies I bet you have "nuked" the HDDs beyond recovery. But if you wanted a final check I wouldn't just check with Recuva but also a RAW file recovery program. PhotoRec is the only free one I have (does more than photo files).

mjf said:

Aside from Government agencies I bet you have "nuked" the HDDs beyond recovery. But if you wanted a final check I wouldn't just check with Recuva but also a RAW file recovery program. PhotoRec is the only free one I have (does more than photo files).

Thanks I will give the Photo Rec a go on the next Nuking job, likely to be later this week!