Opening: Latches or screws should provide easy access
Earthing: Touch the metal chassis inside the computer case
Safety: Unplug the computer from the mains
Locating: Hard drives are typically under CD or floppy drives on desktops
Removing: Disconnect the wires at the back of the hard drive Remove any screws that fix the hard drive to the chassis and slide it out
Smashing: The more thoroughly the better
The only way to stop fraudsters stealing information from old computer hard drives is by destroying them completely, a study has found.
Which? Computing magazine recovered 22,000 "deleted" files from eight computers purchased on eBay.
Freely available software can be used to recover files that users think they have permanently deleted.
While Which? recommends smashing hard drives with a hammer, experts say for most consumers that's a step too far.
Criminals source old computers from internet auction sites or in rubbish tips, to find users' valuable details, and a number of recent cases have shown the dangers in disposing of second-hand equipment.
A number of software solutions exist to more definitively erase files and information.
The most straightforward solution, according to Which?, is complete destruction - and it recommends using a hammer - but it should be noted that destroying the hard drive could release toxic materials when smashed.
It must be done with caution also because those smithereens contain environmentally harmful materials so they should be recycled - for instance at the vendor from whom a new hard drive is purchased.
However experts advise that even a treatment with a hammer may not be the end of your data.
Expensive and sophisticated techniques could be used to recover deleted data, even from a hard drive platter that has been physically damaged.
But for most people, the freely available deleting software or a simple hard drive formatting procedure should make the data sufficiently difficult to retrieve as to not be worth a criminal's time.
"You can get a credit card number on the internet for about ten pounds from credit card thieves," says Rupert Goodwins, editor of technology news website ZDNet.
"So nobody's going to spend more than ten pounds trying to nick your credit card number off your hard disk."
Mr Goodwins argues that the free software is as effective as the hammer - indeed, he argues it is as effective as the software that can be quite costly - and says that for reasons of safety he himself would not take the hammer approach.
"Unless you're a spook or the kingpin of a criminal consortium, there's no need to go out and buy deleting software and no need to put a hammer through the damned thing," Mr Goodwins told the BBC.
"If you're that worried, get rid of it properly: burn it or put it in acid."
Darren Waters investigates what it takes to destroy a hard drive and its data
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