'Ctrl' ,'Alt' and 'Delete' problem

I 've just updated my computer to xp home sp2 version but I find a problem : When I press 'Ctrl' ,'Alt' and 'Delete', it shows a message" 工作管理員已經被你的系統管理員停用", can any experts tell me how to open the 'Ctrl' ,'Alt' and 'Delete' function? Thank you!