Even then, it may still be possible to retrieve the original data, but only by very dedicated experts with extremely powerful recovery software.

A clean start

Another way to clean your hard drive is to reformat it and re-install your operating system.

This is a technical operation, so you should only try it if you are confident about what you are doing, or you know someone who is!

Please note that formatting your hard drive using the 'Format' command does not always erase the data completely.

If you want to find out about reformatting your hard drive, there are some useful tips at Cyberwalker.

A messy end

If you are still worried that the information on your computer may fall into the wrong hands, you can destroy your hard drive.

You can take the hard drive out of your computer and either burn it, or drill holes in it so no-one else will be able to use it.

However, this is an extreme solution, and it's a shame to destroy your hard drive when a charity would gladly accept it as a donation.