HKEY_LOCAL_MACHINE
- Hardware : Stores data describing the hardware that Windows XP detects as it starts. The operating system creates this key each time it starts, and it includes information about devices and the device drivers and resources associated with them. This key contains information that IT professionals find useful during a network inventory.
- SAM : The SAM subkey stands for Security Accounts Manager. In this section, you’ll find the user and group database which controls who has access to Windows along with each set of individual personal settings. Theoretically, you can make edits to this part of the registry and alter the way that users interact with Windows. In practice, this is extremely complicated and extremely dangerous. It’s best to leave any such work to automated software that can tackle the registry with accuracy.
- Security : The SECURITY subkey contains all of the policy data that the system associates with Windows and the various programs and applications. You should not go in to edit this part of the HKEY_LOCAL_MACHINE, nor should you have any reason to in the first place.
- Software : The SOFTWARE subkey is a huge sprawling mass of classes and IDs that make up the main configuration data for nearly everything that is installed on your Windows system – including the core Windows files that form the actual workings of the operating system. One wrong edit here and you’ll find yourself locked out of Windows and facing a major restoration job.
- System : Contains control sets, one of which is current. The remaining sets are available for use by Windows XP.