Difference between Administrator ,Power User, Backup Operator, Guests and User for windows 7

Administrators:
      Members of the Administrators group have complete and unrestricted access to the computer and can perform all administrative tasks. The built-in Administrator account is a member of this group by default and should the Windows7 Professional system be joined to a domain, (or domains) the Domain Admins group of the domain(s) joined will be added to the local Administrators group as well.
                           

Power Users:
      Members of the Power Users group can create and modify local user accounts on the computer and share resources. Effectively, they are one group lower in authority on a local system from the Administrators group in that they possess most administrative powers with certain restrictions.
Basically, 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 system wide 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.

Backup Operators:
      Members of the Backup Operators group can use Windows Backup (NTBACKUP) to back up and restore data to the local computer. Being in this group allows them to override security restrictions for the sole purpose of backing up or restoring files.

Guests   
  Members of the built in Guests group are limited to only having access to specific resources for which they have been assigned explicit permissions for and can only perform specific tasks for which they have been assigned explicit rights.
This is nearly the same access level as members of the Users group except for some additional restrictions.

By default, the built-in Guest account is a member of the Guests group. When the Windows 7 Professional system is joined to a domain, (or domains) the Domain Guests group of the domain(s) joined will be added to the local Guests group as well.

Users:
      Members of the Users Group are prevented from making accidental or intentional system-wide changes and they are only slightly higher in the permission scheme than the Guests Group.
Members of the Users group are limited to only having access to specific resources for which they have been assigned explicit permissions for and can only perform specific tasks for which they have been assigned explicit rights.

When a new user is created on a Windows 7 Professional system it is added to the Users group by default.

When the Windows 7 Professional system is joined to a domain, (or domains) the Domain Users group of the domain(s) joined will be added to the local Users group as well.

Published By
S.G.Godwin Dinesh.MCA
Sr.System Administrator