How can I activate my TV as a monitor using Windows 7?:
Right click on the desktop and select Screen Resolution. The Screen Resolution window will appear.
Both the computer and TV displays should appear in the list. If only one appears, click the Detect button. If both displays appear, click on the Multiple Displays drop-down menu and select Extend These Displays.
Select Monitor 2 and adjust the resolution to match the compatibility of your television set.
Confirm that the image appears on both screens, then click the Keep Changes button.