Windows registry is basically a database that stores various configurations and settings for Windows, hence it should be backed up regularly if possible.
Here is how to do it (to backup registry, make sure to have admin rights) :
1. In the search box that shows up on clicking Windows orb, type “regedit” to launch Registry Editor.
2. Select File > Export.
3. Choose a path where the backup will be stored, to backup the whole registry, select the option of All next to Export range. (It is best to maintain a backup on a thumb drive or any external device just to have some redundancy.)