Horror stories about what? Do you mean filesystem integrity or the physical drive itself? If you think there might be malware or a rootkit on board then erasing the previous owner's personal files (securely or otherwise) won't help.
But if you just want to securewipe the previous owner's files(why bother, just delete 'em and empty the Recycle Bin), try Eraser -
http://www.heidi.ie/eraser/ or SDelete -
http://www.microsoft.com/technet/sys...k/SDelete.mspx
Better still, wipe the drive and install Kubuntu -
http://www.kubuntu.org/ - or Mepis -
http://www.mepis.org/ - Linux
