(quoted from post at 06:29:21 01/31/16) 7 I think. Does it make a difference?
Just for a link to a guide if it's 7. Automatic backup.
http://www.howtogeek.com/howto/1838/using-backup-and-restore-in-windows-7/
You can plug in your drive, manually start a backup, and it will take care of it if you don't want to manually copy files and folders. If your computer fails, or you get a new one, plug in the backup drive, go in and restore, it automatically puts your files where they belong. It keeps multiple versions too if you accidentally delete something.
I don't know how big your files are, flash drives work, external hard drives have more room. I like this kind, they are a regular laptop size hard drive, and it's only got one plug to plug in, it's powered by USB (some external hard drives need electric plugged in too). They've rarely had smaller ones on clearance at Walmart for $30 or so. I've got a couple of my own, one is 6 years old, no issues. This is an ok price if it stays in stock, this is a reputable store selling on ebay if you've never heard of them, I've ordered from them before.
http://www.ebay.com/itm/WD-My-Passport-Ultra-2TB-USB-3-0-Portable-Hard-Drive-2015-Newest-Model/391370197040
https://en.wikipedia.org/wiki/Adorama
There are online backup services, some paid, some free. Google has a fair amount of file and photo backup. Flickr also has a lot for photos and videos. And Microsoft has some, but less than they used to. Dropbox has a small amount. All of them have programs that make the process fairly automatic. If you have unlimited Internet, they are decent options without having to pay money. And it doesn't hurt to have more than one backup method. If you are interested, I can explain the options, not difficult to set up. Carbonite is a good pay option.