You may have the Task Manager disabled in your Windows Vista installation. This may be because of many reasons. For example, a malicious program (malware) can infect and disable the task manager in your Windows Vista installation. But you can easily enable it again. Here is how :
- Press the key combination Windows logo key + R to open the Run dialog.
- Type regedit in the Run dialog and press Enter. This would start the Windows Registry Editor.
- In the Registry Editor, navigate to
HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionPoliciesSystem
- Double-click on DisableTaskMgr and change the value to 0.