c:\windows\systems32\lsass.exe terminated unexpectedly – status code 0

Hi I receive this message [paraphrased]”c:\windows\systems32\lsass.exe terminated unexpectedly – status code 0 – system will shutdown in xx seconds” on a Windows 2000 Professional O/S Gateway laptop. I received this along tiome ago, but I cannot remember what I did to resolve it and I cannot seem to find a resolution. Does anybody have a helpful tidbit of info?