Backing up computer for the first time?

Ok, so my laptop is having an issue. It's a Lenovo touch screen laptop, and the screen is literally coming off. So I called Lenovo, and they said I could send it in and they d take care of everything, but I might want to back up my computer because they might have to do a factory reset or a system wipe or something. Bottom line, all my files could be erased. So I went into the control panel (I have Window 10) on this computer, and it wouldn t let me copy a system image to a 32 GB thumbdrive that I planned to use to back everything up on. However, it is allowing me to store my files, games, contacts, etc. My question is do I need to have a system image back-up of my computer? Or can I just back-up the files? My infotech teacher at school said that often times, if the computer is under warranty, which mine is, they will just send me a new one. And I really can't lose my files.

Just take all you important files and copy them to an external hdd or thumb drive, don't bother with system image. Some things to save, pictures, docs, contacts. Bookmarks, savegames. Its unlikely they will wipe your computer if it is a screen problem anyway