Thats a most interesting reply nihil, this is a a topic that is raised most often, and I must say the answers that are given vary quite considerably.

I've read/heard that data can be recovered using Scanning Electron Microscopes and I'd be really interested in seeing a magnified close-up of a hard-drive (I should do a google on this and yes I do know how to use a SEM - lol).

Anyway - the only true way of been totally secure in deleting data from a hard-drive is with a very large implement (hard drives don't cost that much anyway if you are really paranoid).

As for using software, there are loads out there that claim to delete data - Evidence Eliminator being one (this particular item seems to draw a lot of discussion, but I believe it cannot do what it claims simply because it is not a low level format - oops open for a neg here lol).

If you don't want to swing lump-hammers around then I would suggest using a combination of DBAN and a low level format utility as recommended by your hard drive maker.

The link for DBAN is

http://dban.sourceforge.net/

cheers
humpy