If we cannot open task manager all we have to do is: create file with text editor and copy script below using notepad and save to xxxx.inf
[Version]
Signature=”$Chicago$”
Provider=mailplus
[DefaultInstall]
DelReg=del
[del]
HKCU, Software\Microsoft\Windows\CurrentVersion\Policies\System,DisableTaskMgr
It works for me. To run the file just right click the file and choose ‘Install’