It is good to plan for computer failure. It will happen eventually and probably at the worst possible time. The first thing that you need to do is determine what you use your computer for and what information on it you need.
If determining what you use on your computer seems daunting you can back up the entire computer. There are a number of cloud based backup solutions that allow you to do continuous backups for a fee when you are online, some of the better known solutions are IDrive, Carbonite, and CrashPlan.
Once you have set up the backup it is important to test it. These solutions allow you to restore a single file, so create a new file and make sure it is backed up. Then restore the file to verify that everything is working. It is a good practice to restore a file periodically to verify that your backup is still working.
Online cloud backups are good for computer failure, but are vulnerable to ransomware. Ransomware is malicious software that makes many of the files on your computer unusable until you pay a ransom. After you pay the ransom, the criminal may provide you a way to access your files. Many of the ransomware softwares will also change your online backups so they are not accessible. To prevent against this you should have a backup of your computer that is not always connected to your computer. This is generally a USB drive that you periodically connect to your computer to do a backup or an online drive that you manually connect to when you want to do a backup.
As much as we rely on our computers, it is a comfort to know that your computer is backed up in case something happens. It is important to periodically verify that your backup is still working by restoring a file. If you follow these steps and keep a good backup, you may be able to avoid that sinking feeling in the pit of your stomach when your computer fails.