There is a Microsoft KB which shows you how this can be done, using the winexit.scr screensaver (see below):
This step-by-step article describes how to automatically quit a user's running programs and to log the user off of a workstation after a specified time period.
How to Configure the Winexit.scr Screen Saver:
- Use Windows Explorer to locate the Winexit.scr file in the Windows 2000
Resource Kit folder on your hard disk.
- Right-click the Winexit.scr file, and then click Install.
- The Display Properties dialog box appears with the Screen Saver tab
active. The Logoff Screen Saver entry
is automatically selected. Click
- Select the Force application termination check box to force
programs to quit.
- In the Countdown for n seconds box, type the number of seconds for which
the logoff dialog box appears before
the user is logged off.
- In the Logoff Message box, type the message that appears during the logoff
countdown. Click OK.
- In the Display Properties dialog box, click Preview.
- You see the Auto Logoff dialog box. It displays the logoff message and the
countdown timer. Click Cancel.
- Click OK.
To save you having to download the whole Windows 2000 Resource Kit, head over to petri.co.il and grab the single zipped up file called Winexit from there.