How to Enable Task Manager

Step1
Click on START
Choose RUN
Type REGEDIT
Press ENTER or OK
Step2
Locate HKEY_CURRENT_USER and double click it to Open
Locate SOFTWARE and Double click to open
Locate MICROSOFT and Double click to open
Step3
Locate Windows and Double click to open
Locate CURRENT VERSION and Double click to open
Locate POLICIES and Double click to open
Locate SYSTEM and Double click to open
Step4
Delete the entry that reads DISABLETASKMGR

To Disable this key without deleting, Double Click on it and Modify Value to 0.
Step5
FOR WINDOWS XP PRO USERS :

Click Start
Click 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