Remove Task Manager option

method 1:

Click Start, Run and type Regedit.exe

Navigate to the following branch:HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Policies\ System

               In the right-pane, delete the value named DisableTaskMgr

Close Regedit.exe

                                                 

method 2:

Click Start, Run, type gpedit.msc and click OK.

Navigate to this branch:

User Configuration / Administrative Templates / System / Ctrl+Alt+Delete Options / Remove Task Manager

Double-click the Remove Task Manager option.

Set the policy to Not Configured.