I dont know how the 'FIX' is working. Maybe its creating some problem. But you should enable TaskManager correct way:
1. Type
gpedit.msc in StartMenu->Run and press
Enter.
2. Expand the treeview in left as seen in picture.
3. Double click on
Remove Task Manager and select
Disable.
4. Restart.
PS: You have to be admin to do that.