If you're reading this, you have a computer. If you have a computer, you need to be doing regular backups. Doesn't matter how much of a pain it is, it's part of owning a computer, same as having the oil changed is part of owning a car. Because there two kinds of hard drives, the ones that have failed already and the ones that are going to fail.
My day job is computer and server support. I see it regularly. I preach it. I preach it to my users well enough that the last couple of major failures the users understood that they had failed to be responsible for their data and that it was gone. Let's consider the possibilities.
1. The hard drive just fails.
2. The laptop gets dropped and the hard drive fails.
3. The laptop has a cup of coffee/tea/water/vodka spilled on it and the hard drive fails.
4. The laptop or computer gets stolen.
5. The computer gets a ransomware virus and every data file gets encrypted.
That last one happened to a user this week and she lost everything.
So, here is some advice. Backup. Here's some detailed advice. Buy a external hard drive large enough to hold three times as much information as all your files. Don't worry about Windows or whatever operating system you are using or the programs. That's easily replaced. It's your files, pictures, and documents you want to save.
The drive you buy may come with backup software, if so and you like it, it may be fine. If not, there is a freeware program called Cobian. I use it. You can set it up to do backups on a schedule, pick what folders and files you want to backup, and pick a location to store them, in this case, your new external drive.
If you want the expanded detailed advice, here it is. Backup once a week, at least once a month, and accept that every day that goes by increases the amount of data you will lose.
If you really care about the data (think photos and video) buy two external drives. Rotate the backups to another location so that if the house burns down you aren't thinking about running in to grab the computer. So that if one of the external drives fails, you still have one backup.
If all of this seems like nonsensical gibberish, it's time to learn more about the technology we all use or pay someone to help you set it up. Because all hard drives fail.
There's an existential question I ask people when I am
UPDATE [Borepatch] 31 October 2014 14:31: This is a really, really important post by ASM826. Computers are cheap and easily replaced; data is precious and literally irreplaceable. He and I were talking on the phone when he brought this up, and I asked him to post about it. If you do not have a backup plan in place (or heck, even if you do*) run, do not walk to get Cobian or something. I've never met anyone whose data didn't have any value. ASM826 does this for a living; I trust him on this.
* The comparison to firearms is apt: two is one, and one is none. If you only have one backup method, you actually don't have any.