Windows has 2 different backup capabilities. One is a file/folder backup that basically just backs up things like your documents,photos, music, desktop etc but not the OS or installed programs. The other is system images which are a snapshot of everything needed to effectively replace your whole OS partition even to a new HDD. I recommend you separate the 2 functions by selecting "Let me choose" in the backup configuration and untick the system image box but leave everything else at the default settings. To make an image use the "create a system image" button on the left in the backup and restore window. For more details on creating and restoring images see the tutorial section.
Having said all this I strongly recommend (free) Macrium Reflect for system images.