User Accounts in Windows

Local user accounts allow users to log on at and gain access to resources on only the computer where the local user account was created.
When you create a local user account, Windows XP creates the account only in that computer's security database, which is called the local security database. Windows XP does not replicate local user account information to domain controllers. After the local user account exists, the computer uses its local security database to authenticate the local user account, which allows the user to log on to that computer.

Do not create local user accounts on computers running Windows XP that are part of a domain, because the domain does not recognize local user accounts. Therefore, the user is unable to gain access to resources in the domain and the domain administrator is unable to administer the local user account properties or assign access permissions for domain resources.

Built-In user Accounts:

Windows XP automatically creates accounts called built-in accounts. Two commonly used built-in accounts are Administrator and Guest.

1. Administrator

Use the built-in Administrator account to manage the overall computer and domain configuration, such as creating and modifying user accounts and groups, managing security policies, creating printers, and assigning permissions and rights to user accounts to gain access to resources.
If you are the administrator, you should create a user account that you use to perform non-administrative tasks.

Note: You can rename the Administrator account, but you cannot delete it. As a best practice, you should always rename the built-in Administrator account to provide a greater degree of security. Use a name that does not identify it as the Administrator account because they do not know which user account it is.

2. Guest

Use the built-in Guest account to give occasional users the ability to log on and gain access to resources. For example, an employee who needs access to resources for a short time can use the Guest account. This account is disabled by default. Note: The Guest account is disabled by default. Enable the Guest account only in low-security networks and always assign it a password. You can rename the Guest account, but you cannot delete it.