In tip 2050, I discussed the rundll32.exe user32.dll,LockWorkStation alternate to using CTRL+ALT+DELETE and pressing Lock Computer.

In tip 3590, we scheduled rundll32.exe user32.dll,LockWorkStation on your clients computers.

W2KLockDesktop is a freeware application, that will lock your Windows 2000 and Windows XP computers.

NOTE: You can run W2KLockDesktop remotely, using PsExec.exe or Workstation.bat.