The HKEY_USERS subtree contains all actively loaded user
profiles. HKEY_USERS has at least three keys.
.DEFAULT, which stores the profile used when no users are
logged on to the computer (such as when the CTRL+ALT+DELETE logon
prompt is displayed).
A subkey named for the Security Identifier (SID) of the current
local user. This subkey contains the current user's profile. If the
user is logged on remotely, the data for their profile is stored in
the registry of their local computer. The data in
HKEY_USERS\<SID> also appears in HKEY_CURRENT_USER.
A subkey named for the Security Identifier (SID) of the current
local user with the _Classes suffix. This subkey contains the
current user's Classes. The data in HKEY_USERS\<SID>\_Classes
is also contained in HKEY_CLASSES_ROOT.
In Windows 2000 the default user profile is not stored in
the registry. It is stored on the system drive in \Documents and
Settings\Default User [WINNT]\Ntuser.dat.