"Task Manager has been disabled by your administrator."

Enable Your Task Manager One Easy Step :

Enable or Disable Task Manager for the Current User...

http://www.dougknox.com/xp/utils/xp_taskmgrenab.htm

[Courtesy of MS-MVP Doug Knox]

If the method mentioned above does not work, You might try

* Open Registry Editor (Regedit.exe) and navigate to:

HKCU \ Software \ Microsoft \ Windows \ CurrentVersion \ Policies\ System

* In the right-pane, double-click DisableTaskMgr and set it's data to 0
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