for which you can take PC World to court for, but you can report them to the Information Commissioner, and you say you've done that.
Please bear in mind that for any action in respect of compensation to succeed you would have to show that you had suffered a loss as a result of the disclosure of your personal data - either a material loss (of money) or a loss of reputation or standing in the community. Such matters are always complex, and it's best not to contemplate such a course unless you have a very good case.
Perhaps you could post back with the exact detials of what "all our details" means - was the hard drive sold with a new machine? How long had you had the Packard Bell machine?
Before you write to anyone perhaps you could let me have the information by email as well? Just use the link in the blue square at top left of this page.