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.