the default profile, either in system drivers and services or in the applications) as well as the "Hardware Profiles\Current" subkey which is dynamically linked to one of these profiles. The "HKLM\SOFTWARE" subkey contains software and Windows settings (in the default hardware profile). It is mostly modified by application and system installers. It is organized by software vendor (with a subkey for each), but also contains a "Windows" subkey for some settings of the Windows user interface, a "Classes" subkey containing all registered associations from file extensions, MIME types, Object Classes IDs and interfaces IDs (for OLE, COM/DCOM and ActiveX), to the installed applications or DLLs that may be handling these types on the local machine (however these associations are configurable for each user, see below), and a "Policies" subkey (also organized by vendor) for enforcing general usage policies on applications and system services (including the central certificates store used for authenticating, authorizing or disallowing remote systems or services running outside the local network domain). The "HKLM\SOFTWARE\Wow6432Node" key is used by 32-bit applications on a 64-bit Windows OS, and is equivalent to but separate from "HKLM\SOFTWARE". The key path is transparently presented to 32-bit applications by WoW64 as HKLM\SOFTWARE (in a similar way that 32-bit applications see %SystemRoot%\Syswow64 as %SystemRoot%\System32) HKEY_CLASSES_ROOT (HKCR) Abbreviated HKCR, HKEY_CLASSES_ROOT contains information about registered applications, such as file associations and OLE Object Class IDs, tying them to the applications used to handle these items. On Windows 2000 and above, HKCR is a compilation of user-based HKCU\Software\Classes and machine-based HKLM\Software\Classes. If a given value exists in both of the subkeys above, the one in HKCU\Software\Classes takes precedence. The design allows for either machine- or user-specific registration of COM objects. HKEY_USERS (HKU) Abbreviated HKU, HKEY_USERS contains subkeys corresponding to the HKEY_CURRENT_USER keys for each user profile actively loaded on the machine, though user hives are usually only loaded for currently logged-in users. HKEY_CURRENT_USER (HKCU) Abbreviated HKCU, HKEY_CURRENT_USER stores settings that are specific to the currently logged-in user. The HKEY_CURRENT_USER key is a link to the subkey of HKEY_USERS that corresponds to the user; the same information is accessible in both locations. The specific subkey referenced is "(HKU)\(SID)\..." where (SID) corresponds to the Windows SID; if the "(HKCU)" key has the following suffix "(HKCU)\Software\Classes\..." then it corresponds to "(HKU)\(SID)_CLASSES\..." i.e. the suffix has the string "_CLASSES" is appended to the (SID). On Windows NT systems, each user's settings are