» Standard Standard user accounts can use most software and can change system settings that do not affect other users or the security of the computer.
» administrator Administrator user accounts have complete access to the computer and can make any changes that are needed.
Windows 7 includes User Account Control as a way to enhance computer security by ensuring true separation of standard user and administrator user accounts. Because of the User Account Control feature in Windows 7, all applications run using either standard user or administrator user privileges. Whether you log on as a standard user or as an administrator user, you see a security prompt by default whenever you run an application that requires administrator privileges. The way the security prompt works depends on Group Policy settings and whether you are logged on with a standard user account or an administrator user account.
When you are logged on using a standard user account, you are asked to provide a password for an administrator account. In a homegroup or workgroup, each local computer administrator account is listed by name. To proceed, you must click an account, type the account’s password, and then click Submit.
In a domain, the User Account Control dialog box does not list any administrator accounts, so you must know the user name and password of an administrator account in the default (log on) domain or a trusted domain to continue. When Windows prompts you, type the account name, type the account’s password, and then click OK. If the account is in the default domain, you don’t have to specify the domain name. If the account is in another domain, you must specify the domain and the account name by using the format domain\username, such as cpandl\williams.
When you are logged on using an administrator user account, you are asked to confirm that you want to continue. You can click Yes to allow the task to be performed or click No to stop the task from being performed. Clicking Show Details shows the full path to the program being executed.
An important related change has to do with elevation of privileges. Elevation allows a standard user application to run with administrator privileges. You can run applications with elevated privileges by following these steps:
1. Right-click the application’s shortcut on the menu or on the desktop, and then click Run As Administrator.
2. When you see the User Account Control prompt, proceed as you normally would to allow the application to run with administrator privileges.
Note : You must run the Command prompt window with elevated privileges to perform administration at the command line. If you do not do this, you will see an error when you try to run an administrator utility or perform a task that requires administrator privileges.
Source of Information : Microsoft - Windows 7 Administrators Pocket Consultant 2010