A number of cases have been highlighted in the press where recycle centres have shipped old computers abroad, and subsequently personal information has been extracted leading to Identity Theft . Ideally before any equipment leaves your possession, you need to ensure that any traces of your previous information are completely removed from the hard disk before disposal.

Searching the internet turns up lots of software for erasing your hard drive. We've experimented with one such tool - Eraser aimed at helping ensure that all data is overwritten numerous times before recycling your hard disk.

So how does it work? You can either choose to erase areas of your disk which are unused, or overwrite the programs on the machine. The best way to ensure all data is removed is to following the following:

1) Insert the unwanted hard disk into another computer - this then becomes the secondary disk in the computer. You need to ensure that you also have another disk in the computer with a working operating system.

2) Remove all existing partitions from the unwanted hard disk.

3) Create a single partition on the disk which is the complete size of the hard disk.

4) Install your eraser program onto the other hard disk and run on the old disk.

You may run into issues with operating systems such as Vista or Windows 7 which appear to prevent you from running the program, and require 'administrator' permission. Ensure that the program is not currently running on the computer (including the system tray in the bottom right hand corner of the screen) and then select to 'run program asadministrator. This is becoming a common option since Microsoft introduced UAC for our protection.

The majority of these programs use a minimal number of overwrites for unused space. We would suggest changing the settings to use Gutmann (35 passes) or similar to ensure that random data is written to the disk sufficient times to ensure no traces of the old data are left.