this is very detailed and exact http://windowsxp.mvps.org/Taskmanager_error.htm
if you cannot do any of those you most likely still have a virus and probably have bigger problems.
I am using XP (service pack 3) as my operating system for my PC. Some months back my PC was infected with a virus (name not known) and subsequently it was cleaned. After that whenever I try to open my task Manager it says " Task Manager disabled by your Administrator". Now how do I enable the task manager for all the users? I am also the administrator.Can somebody help me!!