Task Manager Disabled:

f you are working on Windows XP pro, following steps will help u to enable Task Manager

SOLUTION 1:
Click Start --> Run
Enter gpedit.msc in the Open box and click OK
In the Group Policy settings window, select User Configuration
Select Administrative Templates
Select System
Select Ctrl+Alt+Delete options
Select Remove Task Manager
Double-click the Remove Task Manager option
Disable that option

SOLUTION 2:
Click on Start >> Run and in the Open box type:

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

Click OK.