High Street retailer PC World has yet again breached the data protection Act by selling a computer with a used hard drive which contained private information about its previous owner.

PC Advisor reader Dave Stirrat logged on to our ConsumerWatch forum looking for advice about a problem he'd encountered with PC World. Dave purchased a PC from the retail giant back in July, but after several system errors he returned it for repairs. He was informed by PC World that the machine could not be fixed and was sent a new model to replace it.

As far as Dave knew, his old computer had been destroyed by PC World. But a couple of weeks later he was contacted by a complete stranger ? let's call him Mr X ? who had purchased a 'new' machine from PC World. When setting it up he realised he'd actually been given Dave's hard drive containing all his personal information.

This is not the first time PC World has managed to pass on a secondhand drive to a customer - if you look at past ConsumerWatch columns you'll find similar stories.

PC World finally put its case forward today, over a week after we first contacted its press office, blaming human error for the 'accident'. It claims shop staff mixed up the returned PC with a consignment of new computers. Dave's system was therefore put back on the shelves alongside the new PCs.

"Our returns procedure ensures this doesn't happen," said Hamish Thompson, press officer at PC World. "Returned machines go through an audit process. They are given a store reference and returned to the warehouse.

"All retailers sell products that are returned so long as they are clearly marked. This was a case of human error. The last thing we want to do is mislead our customers," he added.

The information Commissioner is currently looking into Dave's case.

"We have eight guiding principles regarding data protection; [the seventh] places an obligation on [PC World] to protect its customers' personal information," said a spokesman at the Information Commission.

"We have the power to enforce sanctions against PC World if this proves to be a continuing problem, but firstly we will offer them advice on how to ensure they comply with the requirements [of the Data Protection Act] in the future," he added.

Unfortunately, Dave cannot bring a case against PC World as by law only Mr X is able to take action.