thanks to all .
about changing those values in registry i have to say i don't have ' disable taskmgr' in system
under policies!!!
why?
i guess all you mention is for disabling this combination for chaning the way of loging on to system,but i want the way that disable this keys in order to not be able to kill process.
i 'll like to know how can i do it?
i haven't still try those using APIs.i might be my need.

hey nihil you have nice teeth.