| 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. |