Enabling
Copy the following in to Notepad:

Code:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System]
"DisableTaskMgr"=-

Click File > Save as
Choose Save as type: All Files
Save the file to your Desktop as enabletask.reg
Exit Notepad and double click on the file to run it. Choose Yes/Confirm any prompts.

Disabling
Copy the following in to Notepad:

Code:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System]
"DisableTaskMgr"=dword:00000001

Click File > Save as
Choose Save as type: All Files
Save the file to your Desktop as disabletask.reg
Exit Notepad and double click on the file to run it. Choose Yes/Confirm any prompts.