Task Manager has been disabled by your administrator

Error Message: "Task Manager has been disabled by your administrator"

Symptom
When you try to open Task Manager, the following error may occur:

"Task Manager has been disabled by your administrator"

Resolution
This error is caused if the DisableTaskMgr restriction is enabled. To enable Task Manager, try one of these methods:

Method 1
Click Start, Run and type this command exactly as given below: (better - Copy and paste)

Method 2
Download and run this REG fix and double-click it.

Method 3
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 4: Using Group Policy Editor - for Windows XP Professional
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.