Task Manager has been disabled by your administrator

Sometimes, task manager gets disabled due to some virus. You can enable it easily by following the following methods:

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

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

Method 3

Click Start, Run, type gpedit.msc and click OK.
Navigate to this branch:
User Configuration / Administrative Templates / System / Ctrl+Alt+Delete Options / Remove Task Manage
Double-click the Remove Task Manager option.
Set the policy to Not Configured.

By following any of the above methods the problem of task manager will be resolved.