Predefined Keys

HKEY_LOCAL_MACHINE Contains information about the hardware and software on the computer.
HKEY_USERS Contains information about the users of the computer. In particular, this contains any user-specific information associated with hardware or software is stored.
HKEY_CURRENT_USER Contains information about the current user. This is mapped to the default user branch under the HKEY_USERS key.
HKEY_CURRENT_CONFIG Contains information about the hardware configuration of the computer. This typically
HKEY_CLASSES_ROOT Contains information about OLE classes.
HKEY_PERFORMANCE_DATA Contains information about system performance.
HKEY_DYN_DATA Contains information about dynamic data.