"Task Manager Has been Disabled"

When you try to open Task Manager, the following error may occur:
"Task Manager has been disabled by your administrator "

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

REG add HKCU\Software\Microsoft\Windows\CurrentVersion\Policies\System /v DisableTaskMgr /t REG_DWORD /d 0 /f

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.