If in case Windows Task Manager was disabled, these steps will enable it back:

Remove Task Manager Restriction Using Group Policy
1. Click Start > Run
2. Enter gpedit.msc in the Open box and click OK
3. 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 Disabled

4. Exit the Group Policy Editor

Remove Task Manager Restriction Using Free Tool
RRT or Remove Restrictions Tool is a free tool to enable access to different Windows process disbaled by virus infections.

This tool is used to enable access to:
- Registry Tools (regedit)
- Ctrl+Alt+Del
- Folder Options
- Show Hidden Files

Download RRT: click here to donwload