To add a user to the Backup Operators group
Open Computer Management
In the console tree, click Groups.
Computer Management > Local Users and Groups > Groups
In the details pane double-click Backup Operators.
On the Backup Operators Properties dialog box, click Add.
On the Select Users or Groups dialog box, next to Name, type the domain and user name of the person you want to make a backup operator Type the domain name first, then a backslash, then the user name. For example, \\London\William.
Click Add, and then click OK.
To add a user to the Operators Group on a domain controller you must use Active Directory Users and Computers. For more information, click Related Topics.
You must be a member of the Administrators group to designate users as Backup Operators.
To open Computer Management, click Start, and then click Control Panel. Click Performance and Maintenance, click Administrative Tools, and then double-click Computer Management.