Our computers and mobile phones contain all manner of personal data, from documents featuring details of your date of birth and address to financial records and family photos. 

Yet every year thousands of hard drives end up undeleted on the scrap heap or sold second-hand. This presents a real risk of personal information falling into the wrong hands. Data recovery software is simple to use, after all.

But, taking control of your data when it's time to upgrade to a new machine or device is also simple. Follow these steps and your old digital bits won't come back to bite you.

Dispose of your computer responsibly with our guide to recycling an old computer

Deleted files can be recovered

Simply deleting a file from your hard drive doesn't mean it's no longer there – it just means the computer doesn't know where to go and look for it. 

A forensic expert, digital criminal or any ne’er-do-well with the right equipment could easily access every single detail even from deleted hard drives that look empty to the untrained eye. 

Even if you're only passing an old laptop on to a relative, it's still worth taking precautions, in case they don't wipe the machine when they upgrade.

Data-wiping programs

In order to really eradicate data you need to use data-shredding software. These programs  don't just delete data - they overwrite it multiple times to erase all trace, making it almost impossible for anyone to retrieve it. 

There are numerous tools for performing a data deep clean, such as Eraser. The program works within Windows, and should be used to target your folders where you keep files, photos and documents.

To install it, head to the Eraser download site and click on the latest file name under the Build name list. A small .exe file will download to your computer. Click to run and install this.

Eraser will now be a piece of software on your computer - it's simplicity itself to use. Right-click on a file or folder, then click on Eraser for the option to Erase data completely. By default, the program is set to overwrite data 35 times, which can take several hours on a large hard drive. 

Beware: once deleted, there is no recovering your data. Don’t forget to apply the process across your entire computer, including the Recycle Bin.

Manually destroying your hard drive

It might not be the most environmentally friendly option, but taking a hammer to a hard drive can be a therapeutic and effective way of destroying data. 

Of course, it means you can't sell or pass it on to anyone else, but you know the data is destroyed for good.