Enable Task manager, Regedit  and Folder option in some easy steps:

Open Start > Run > Gpedit.msc

REGEDIT:
in Gpedit.msc

User Configuration > Administrative Templates > System > open "Prevent access to registry editing tools" choose enabled > apply > ok      and    open again choose disabled > apply > OK


TASKMANAGER:
in Gpedit.msc

User Configuration > Administrative Templates > System > Ctrl+Alt+Del Options > "Remove Task manager" choose enabled > apply > ok      and    open again choose disabled > apply > OK


Folder Option:
in Gpedit.msc

User Configuration > Administrative Templates > Windows Components > Windows Explorer> " Remove the Folder Option menu item from the Tools menu" choose enabled > apply > ok      and    open again choose disabled > apply > OK