Computer-users rarely think too hard about the data held on their machines.

But this could be data which reveals all manner of personal secrets and may even be embarrassing or incriminating.

The contents of recovered digital diaries, e-mails, letters and notes may seem quite innocent but in the wrong hands they could be more explosive than semtex.

Many people think the best thing to do is to give an old machine away to an enthusiast or sell it to help finance a new computer.

Recycling is a good thing isn't it?

The problem is old data doesn't simply go away.

A skilled forensics investigator can even recover data from hard drives that have been formatted a number of times and show no obvious trace of data when viewed with everyday software.

This has huge implications for anyone whose computer system has held sensitive databases, financial details or any other information that falls under the Data Protection Act.

For many people the only real solution is to physically destroy the hard drive on which the data was held to prevent unauthorised information falling into wrong hands.

There are a number of software packages that claim to erase data or to make it unreadable.

They do this by over-writing the entire hard drive with meaningless bits and bytes in an attempt to obliterate the underlying information.

Unfortunately, they don't work well enough to prevent a determined 'nosy parker' from sniffing out the computer's secrets.

The truth is almost anyone can recover data from an old hard drive if they have the software tools to do the job.

These tools are freely available on the internet and can access data that has been deleted by going 'behind' the conventional directory structure and exploring the raw data held on the hard drive's base memory.

But digital 'clean-up' specialists can achieve effective data wiping.

They use strong magnetic fields to rearrange magnetic data in a way that cannot be recovered. This service is expensive.

Brighton-based Sek Tech sells refurbished computers from across the country.

Sources include the Inland Revenue but area sales manager Paul Williams said hard drives of refurbished machines are thoroughly cleared before they reach Sek Tech.

Recently, a national bank donated 500 obsolete computers to a project designed to assist schools.

Hailsham-based Simon Rooksby sends refurbished machines to impoverished schools across the globe as chairman of Computers for Charities.

This may have been cheaper than paying for the disposal of the equipment and almost certainly engendered a nice warm feeling for those involved in offloading the machines.

But it begs the question, is giving old computers to schools a responsible way of disposing of a growing problem? Education authorities are always short of money and many people may see 'free' computers as a way of making up a budgetary shortfall.

But do we want our children to equate computing with worn-out and outdated machines with suspect hard-drives and inadequate memory?

Surely children need the best IT resources that the country can offer to enable them to learn on machines that are matching industry standards and are capable of running the most up-to-date software?

What do you think?

E-mail evolution and tell us how you think the problem of computer obsolescence should be dealt with. Are local councils doing enough? What else can be done?