ComputerBB

Hi everyone, When I try to access Task Manager (Ctrl-Alt-Del) I get a popup saying ( Task Manager has been disabled by your administrator) I go to regedit and I change to a 0 and I click OK, then the Task Manager starts working, but after I turn the computer OFF and ON, I have the same problem, and I have to do the same, to make work. There are no other accounts on this computer & it is Windows XP. Does anyone have any suggestions?? Many thanks in advance, Carl