In addition, the registry files NTUSER.DAT and USRCLASS.DAT are stored in the profile of each user (C:\Users), which contains the user settings (loaded to the HKEY_CURRENT_USER registry hive).
SYSTEM (HKLM\System) - settings for computer’s hardware, settings for Windows services, drivers, and other low-level information.
SECURITY (HKLM\Security) - Windows security settings.
SOFTWARE (HKLM\Software) - the settings of various applications and the Windows OS itself are stored, common to all users.
SAM (HKLM\SAM) - the settings of all Windows security principals are stored.
DEFAULT (HKEY_USERS\DEFAULT) - a template with user settings used when creating new accounts.
Below is a list of files and registry hives that these files are loaded into when Windows boots (as you see them in Registry Editor):