Common problem likely caused by virus..follow this doc..Method 1, 2 and 3 seem the easiest to understand. Method 4 is what PDS is describing. That doesn't seem to work cuz it doesn't find the gpedit.msc, at least for me, and seems the op as well. Method 3 is good cuz u get to blow your load.
http://windowsxp.mvps.org/Taskmanager_error.htm
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.
http://windowsxp.mvps.org/reg/EnableTM.reg
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
Contact fav SP and blow ur load
PDSAjax said:
You can probably fix it by doing this
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
Set to Not Configured
You may need to restart your computer
Let me know if you need more info