Before disposing of an old computer, securely erase all your data. So the time has come to dispose of your old computer – perhaps it’s too old or you want to sell/give it to someone else. But what to do about all your documents, emails, passwords and personal data stored on the hard drive?
Do you want someone else seeing your private pictures or reading your documents? We showed in a previous article how easy it is to find out a hidden email password – someone could use your old computer to access your email – not just on your old computer but all your future emails too!
The solution is to securely erase all your data – how you do this depends on how you are planning to dispose of the computer and how much time/knowledge you have. Make sure that you have backed up (or transferred onto your new computer) any data you want to keep first:
1. Throw It Out – If the computer is very old or faulty you may be tempted to just throw it in the trash. However, it would still be possible for someone to access the hard drive and recover your personal data (unless you are certain the hard drive itself is totally dead).
If the computer is just old/surplus to requirements then you could follow our article to securely erase it with DBAN or skip to Option 2 below. If the computer is faulty and you are not able to start it or get into Windows then the options to keep your data secure are more limited:
- Put the hard drive in another computer and see the article above on securely erasing it with DBAN OR
- Remove the hard drive and keep it as a backup – you could even buy a cheap USB hard drive caddy/enclosure, put your old hard drive in it and use it as an external USB hard drive OR
- If you want to throw the hard drive away then at least do your best to destroy it first – drop it onto a stone surface several times, use a hammer to ruin the circuit board underneath the drive or drill a few holes through it (taking usual safety precautions). The more damage, the less chance any data can be accessed.
2. Sell/Give It Away – If the computer is still working you may want to sell/give it to a relative or friend/charity. Before doing so it still makes sense to clean up the computer and securely erase your data – you cannot be sure that they will be bothered about the security of your data when they come to dispose of it themselves… There are two options:
- If you know how to reinstall Windows then securely erase the whole hard drive with DBAN as shown in our earlier article here. Then reinstall Windows, drivers and any software/updates OR
- If you want to take the quicker route and leave Windows in place, you just need to securely erase your personal data and history. We will show you how to do this in the next sections:
Erasing Your Data
- First, uninstall any programs you do not want to leave on the computer (particularly if you they have a single license and you need to reinstall them on your new computer) e.g. printer/scanner/webcam software, MS Office, family tree software, games you have bought etc.
- Now create a new user account – the steps are virtually the same in XP, Vista and 7 (words in brackets may appear in some versions): click Start, Control Panel, (Add or Remove) User Accounts, Create A New Account then give the new user a name and choose an account type of (Computer) Administrator.
- Log off your own user account (or restart the computer) and log into the new user account.
- Now delete your old user account(s) – click Start, Control Panel, (Add or Remove) User Accounts, select the old account to change and choose to delete it – you will be asked if you want to keep the files from the deleted account. Make sure you choose to ‘Delete’ all that user’s files. Repeat this step for all the old user accounts on the computer except the Guest account – you should end up with just your new user and the Guest account.
You have now deleted all the old user documents/pictures/emails etc but they can still be retrieved by someone with technical knowledge. To delete them permanently and prevent recovery, follow the next steps to overwrite all of the free space on the hard drive using Ccleaner:
Erase Free Space using Ccleaner
- Download Ccleaner from Filehippo here and install it.
- Delete all temporary files by following the steps as shown in our article to delete temporary files with Ccleaner.
- Now click on the Tools tab in the left panel of Ccleaner and click on the Drive Wiper tab as shown below:
- In the right panel of Drive Wiper:
- Set the Wipe option to ‘Free Space Only’. Set the Security option to Simple Overwrite (one pass) – see Note below for other options. In the Drives section, tick all your hard drive(s) listed – usually you will just have a C: drive. In our case above we would tick all five drives – C: through to G:
- Now click the Wipe button to start the wiping of all free space on the drive – this will erase all the previously deleted data securely and permanently. It may take an hour or much longer, depending on the size of your hard drive.
Note: Simple Overwrite (1 pass) in Ccleaner writes over all the ‘free space’ that still contains your deleted files once - this is considered sufficient for most situations but if you have really confidential data and want to be extremely sure then you can select 3 or 7 passes in the Security option box although this will take 3 or 7 times as long (may add up to many hours or even days).