If you have upgraded your computer and you want to donate or recycle your system there are a few precautions you should take to keep your data safe.
Before you do anything a backup may be needed. If you know that you have data that is important to you then backups should be done regularly.
There are physical backups like on a flash drive or external hard drive. These backups can be scheduled to done regularly with backup software, whether it's your operating system's program or a third party program.
You could also use cloud backups which saves your data to the internet. You can use programs like Dropbox or Google Drive.
Operating System Reinstall
If you are donating the computer and want to have it functioning for the next person, then a reinstall is what you need to do. Depending on what operating system you are running there are a few methods to wiping your system.
Most computers come with an operating system reinstall disc that can be used when you need a fresh install.
If you don't have one then you may have a recovery partition already on your system that you can use. The options should be available in your boot options.
Remove Hard Drive
If you do not need the computer working and you just want to keep your data from getting stolen, taking out your hard drive is the best option.
Most computers have the hard drive readily accessible. On a desktop you most likely need to remove the side panel to find your hard drive. Unplug, and unscrew or slide it out.
On a laptop it may be a little more tricky. On the bottom of your laptop you may see a small panel with a symbol of a disc. If you can open that panel you can easily unplug your hard drive. If you have no panels you may need to open up your whole laptop, so you might need to request some extra help at that point.
Your data can be very sensitive and important. You should never give your system away or throw it away before you know that there is no data that can be accessed.