Q. I have used Google's Picasa photograph software for many years across several different PCs, resulting in my account being peppered with duplicate images. Can I delete them in one go?

A. Picasa is excellent for managing a photographic collection. It is able to detect potential multiple images, and offer deletion, but image by image not in a single click. There is free software that will provide bulk deletion, of which more later, but first Picasa. Use Picasa to backup your images before doing anything, just in case! Next, open Picasa, click on Tools/Experimental/Show duplicate files. Picasa will then scan your PC, and any attached drives, and list those that it thinks may be duplicates. Delete them as necessary, making sure that you keep one copy! For the courageous, there is the free VisiPics tool, which will scan, locate and delete "similar" images as well as obvious duplicates.

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. Go to http://www.itforcharities.co.uk/donorinf.htm for information on offering your old laptop or PC to charity.