XP includes a feature called Fast User Switching for both Home and Professional systems, and it's enabled by default. Fast User Switching is a nice feature on a system that has more than one account because it allows another user to log on and use the computer without the other user having to log off.
Why is this a big deal? Because when a user logs off, all applications are closed. Let's say, for example, that you're working on a big Excel spreadsheet, and your spouse wants to open up Outlook Express to quickly check email. He or she can do this by clicking Start | Log Off and then selecting the green Switch User button instead of the yellow Log Off button. When you switch users again, you still have the spreadsheet open just as you left it. In addition, your spouse's work environment won't be changed the next time he or she uses the computer again.
To enable and disable Fast User Switching, do the following:
Open the Control Panel and then select the User Accounts category.
Click the "Change the way users logon and log off" item to display the User Accounts dialog box, where you can set logon and logoff options, as shown in Figure 3-8.
Figure 3-8. Enable Fast User Switching.
A few additional notes about Fast User Switching:
A couple features are disabled when using Fast User Switching. Most significant among these is the Offline Files feature. However, recall from Chapter 2, "Windows Installation and Upgrade," that Offline Files are not available with an XP Home machine anyway. When you are using Offline Files on a Professional machine, and you try to change the way users log on and log off, you're prompted to disable Offline Files.
Fast User Switching is not available when an XP Professional machine is part of a Windows server domain.
Fast User Switching is not very secure and therefore is best suited for XP Home installations.
Fast User Switching requires more computer resources, such as memory, than traditional logging off. You might notice a slowdown in performance when multiple users are logged on and you're switching back and forth between these users. Because logging off closes programs, it also frees resources for the next user who logs on, and the computer generally runs faster.