Trick of the Week 1 - Use Run as... function

First Procedure

In Windows 2000 / XP, you can run programs as a different user than the currently-logged on user. To use it in Windows 2000, the RunAs service must be running and in Windows XP, SecondaryLogon service must be running. Please check first, if you are running those services.

Then press SHIFT key on the keyboard and right click on the application you wish to setup (eg setup.exe). In the menu you'll see options "Run As...". Click it and you are present with this window bellow. Click the the following user option, type or select the User name, type the Password, and then click OK.

This screen was taken from Windows XP, in Windows 2000 it's a bit different. In Run As Other User, type the User name, Password, and Domain, and then click OK. That's it.

Second Procedure (apply via registry):

This is more advanced procedure (Please update Windows XP database before applying this tweak, becouse a bug has been found in database.). You can again check if the service is running and then use Registry Tweaker to add "Run as..." option to menu, so it's available for you all the time (no need for pressing SHIFT key). To do this find "Run as... option from the context menu" tweak in Windows XP database and apply it. Reboot PC.

Tool: Download it here.
You need Microsoft Framework 2.0 to run this tool. Get it here.