When you use the Tasklist.exe utility included in Windows XP Professional, the following error may be displayed:
ERROR: Class not registered
This error might occur if Windows Management Instrumentation (WMI) components are missing or not registered correctly.
To re-register the WMI components, run the following commands at the command prompt:
cd /d %windir%\system32\wbem
for %i in (*.dll) do RegSvr32 -s %i
for %i in (*.exe) do %i /RegServer