Workarounds
The shutdown sequence can be aborted by pressing start and using the Run command to enter shutdown -a. This aborts the system shutdown so the user may continue what he or she was doing. The shutdown.exe file is not available by default within Windows 2000, but can be installed from the Windows 2000 resource kit. It is available in Windows XP. A second option to stop the worm from shutting down a computer is to change the time and/or date on its clock to earlier; the shutdown time will move as far into the future as the clock was set back.
Read more about this topic: Sasser (computer Worm)