You can run programs as a different user than the currently logged on user in Windows XP. The Secondary Logon service must be running to do this in Windows XP. The services RunAs and Secondary Logon are the same service with different names. This guide will teach you on how to enable and use the Run As command on a Windows XP-based computer.
Specifications
You must use Windows XP in your computer.
Logging on to the main user account of your computer is required.
Enable the RunAs the Secondary Logon service on a Windows XP-based computer
The service that is appropriate to run the Run As command automatically initiated when you install Windows. On the other hand, an administrator can disable the service. You can re-activate it by following these steps:
1. As an administrator, you may require to log on to your computer.
2. Place your cursor on “my computer” then press the application key. Next, choose “Manage.”
3. Under Computer Management, dilate the Services and Applications node, and then select Services.
4. Perform this step:
In the details pane, place your cursor under Secondary Logon service and press the application key, and then choose Properties.
5. Set Startup type to Automatic in the Properties dialog box, and then choose Start.
6. Press enter on OK button to close the Properties dialog box after the computer starts the service, and then exit Computer Management.
The service that is appropriate to run the Run As command is now active on your computer.
Apply the Run As command with a shortcut
1. Move to the shortcut item. Press the window logo key, choose Programs, and then explore the shortcut item in the Programs menu.
Navigate to the proper location of the shortcut if it is not located in the Programs folder of the Start menu.
2. Press SHIFT and hold while you pressing application key in the shortcut item, and then choose Run as.
3. Perform this step:
In Run As, select the following user option, enter or choose the User name, enter the Password, and then choose OK.
Troubleshooting
it could fail if the references that are used to connect to the network share are different from the references that are used to start the program If you try to start a program like an MMC console or a Control Panel item from a network location by using the Run As command. The references applied to run the program may not be able to obtain access to the same network share.
The Run As command will not activated from the Local System account in Windows XP Service Pack 2.
How to enable and use the "Run As" command when running programs in Windows 
