How To Use the Fast User Switching Feature in Windows XP
Fast User Switching is enabled by default in Windows XP Home Edition and Professional on computers with more than 64 megabytes (MB) of RAM. However, Fast User Switching is not available on Windows XP Professional-based computers that are part of a domain network.
Enable or Disable Fast User Switching
Note: To enable Fast User Switching, you must also enable the Use the Welcome screen option. This feature cannot be used if your computer is a member of a domain.
To enable Fast User Switching:
Log on to the computer as an administrator.
Click Start, click Control Panel, and then click User Accounts.
Click Change the way users log on or off.
If it is not already selected, click to select the Use the Welcome screen check box.
NOTE: The Use Fast User Switching check box is unavailable until you click to select the Use the Welcome screen check box.
Click to select the Use Fast User Switching check box, and then click Apply Options. Quit the User Accounts tool.