Instructions:

  1. Click "Start" button
  2. Click "Run..."
  3. Type "regedit" + press enter
  4. Navigate to "HKEY_CURRENT_USER \ Software \ Microsoft \ Windows \ CurrentVersion \ Policies \ System"
  5. Create or modify "DisableTaskMgr"
    0 = Enabled
    1 = Disabled
  6. Exit registry
  7. Restart computer
  8. Repeat step 1 to 7 for each user you want avoid using the task manager