You should back up your Files in the event of a system crash or virus. (if you have more than one profile on the computer, you will need to backup the data on more than one location)

Here is information on Backing up your system

Below is how I back up my files (everyone does it different but this is what I do)

I have a second internal hard drive and and external hard drive. I use Karen's Replicator (it is free and an excellent program that backs up your system without requiring your interaction)

I have two different folders that I back my files to. I created these two folders on my secondary internal hard drive. They are as follows

1. Databackup(date it was created) - this is the folder I back my files to

2. Startup menu - This is the list of items in my startup folder so if my startup menu (startup menu is the menu you click on to access a program)

I selected the files I want backed up on my C drive and instructed Karen's Replicator to back up those files every morning at 3 AM to my secondary internal drive. I also have Karen's Replicator backup my secondary internal drive to an external hard drive so if one of them dies I still have a copy.

It is a good idea to backup the entire user folder (if you have a storage drive big enough for it). However sometimes a protected file can interfere with a backup. Sometimes the user folder will copy without an issue but sometimes it does. By backing up the user folder, chances are you have backed up all your important files (not always the case but usually does). Therefore I would backup individual folders also.