[Blast]

Отличия в правах и привилегиях, подробнее смотрите здесь: Logon rights и Privileges - там касательно серверной ОС, но представление получить можно.

[band1t]

Во-первых, это не учётки, а группы, в которые могут быть добавлены учётные записи пользователей. Простые пользователи могут запускать только сертифицированные приложения, т.е. приложения, имеющие цифровую подпись, а опытные - любые.

[Vadikan]

Power Users The Power Users group primarily provides backward compatibility for running non-certified applications. The default permissions that are allotted to this group allow this group's members to modify computerwide settings. If non-certified applications must be supported, then end users will need to be part of the Power Users group. Members of the Power Users group have more permissions than members of the Users group and fewer than members of the Administrators group. Power Users can perform any operating system task except tasks reserved for the Administrators group. The default Windows 2000 and Windows XP Professional security settings for Power Users are very similar to the default security settings for Users in Windows NT 4.0. Any program that a user can run in Windows NT 4.0, a Power User can run in Windows 2000 or Windows XP Professional. Power Users can: • Run legacy applications, in addition to Windows 2000 or Windows XP Professional certified applications. • Install programs that do not modify operating system files or install system services. • Customize systemwide resources including printers, date, time, power options, and other Control Panel resources. • Create and manage local user accounts and groups. • Stop and start system services which are not started by default. Power Users do not have permission to add themselves to the Administrators group. Power Users do not have access to the data of other users on an NTFS volume, unless those users grant them permission. Users The Users group is the most secure, because the default permissions allotted to this group do not allow members to modify operating system settings or other users' data. The Users group provides the most secure environment in which to run programs. On a volume formatted with NTFS, the default security settings on a newly installed system (but not on an upgraded system) are designed to prevent members of this group from compromising the integrity of the operating system and installed programs. Users cannot modify systemwide registry settings, operating system files, or program files. Users can shut down workstations, but not servers. Users can create local groups, but can manage only the local groups that they created. They can run certified Windows 2000 or Windows XP Professional programs that have been installed or deployed by administrators. Users have Full Control over all of their own data files (%userprofile%) and their own portion of the registry (HKEY_CURRENT_USER). However, user-level permissions often do not allow the user to successfully run legacy applications. Only the members of the Users group are guaranteed to be able to run Certified for Windows applications. (For more information, see the Certified for Windows Program on the Microsoft Web site. To secure a Windows 2000 or Windows XP Professional system, an administrator should: • Make sure that end users are members of the Users group only. • Deploy programs that members of the Users group can run successfully, such as certified Windows 2000 or Windows XP Professional programs.

Источник

На русском вроде нет документации в сети, но можно в справке поискать встроенной.