Backing up your data on your hard drive is important because a system crash or virus may make it impossible to retrieve your data otherwise. Most modern computers have an automatic function that will allow you to periodically back up important files to a separate partition of your hard drive that would be safe in the event of a hard drive crash. This requires you to set up specific time points and to designate which files to back up and where to save them, so take some time when you first get a computer to become familiar with this process. Backing your files up to a partition of your hard drive is a great first line of defense in case something happens, but there may be times when this is not enough.
For the best security, it is recommended that you back up your files to an external hard drive. An external hard drive can hold up to several terabytes of data and often do not take up more room than a small book. You can keep the external hard drive permanently attached to your computer and set specific times that it will automatically back up your files, or you can manually update your files yourself. It is recommended to set up automatic updating since you will not forget to back up your files. If you do not have an external hard drive, a USB thumb drive can be used to save important documents in case of emergency.
In the simplest form of backing up your files, you can send a file as an email attachment to yourself, which will allow you to access the file anywhere in the world. Always save another copy of important files in a different drive and you will be much happier if something were to happen to your computer.