Q. How do I clear my data off an old PC or laptop, and what is the best way of disposing them? (Question courtesy of The Sunday Times.)

A. The only absolutely sure way of destroying data is to physically destroy the hard disk, but it will also ensure that no-one wants your old PC! (They have little value anyway, of course.) A better solution if you want to pass your laptop or PC to someone else, or a charity - of which more latter - would be to download the free Eraser program from http://www.eraser.heidi.ie/. This not only deletes, but overwrites data multiple times, whilst normal deletion merely changes a file's header leaving the rest of the data intact. Military standard decryption software might be able to restore data after running Eraser! Go to http://www.itforcharities.co.uk/donorinf.htm for information on offering your old laptop or PC to charity.