After connecting your computer to a TV, it is common to find that the computer doesn't recognise the TV. When this happens, you can correct the problem quickly without having to open the computer up or download any software. All you need to do is set the TV to the proper display mode and you can have your computer recognise your TV with a couple clicks of the mouse.
Set the TV to the correct input mode by pressing the corresponding button on the remote. The correct input mode depends on the type of cable you used to connect your computer to your TV. If your computer is connected to your TV through an HDMI cable, press then the "HDMI" button, if it's connected through a DVI cable, press the "DVI" button, if it's connected through a VGA cable, press the "PC" button and if it's connected through composite cables, press the "Video" button.
Connect a computer monitor to your computer while leaving the TV connected to your computer. If the computer is a laptop, use the built-in screen. Go to the desktop on the computer, find an empty space and click the right mouse button. Do not click on a desktop icon. If your desktop is completely filled with icons, position the mouse in the space between icons. After clicking the right mouse button, a menu will appear.
Hover the mouse over the "Graphics Options" selection on the menu. Another menu will appear; hover the mouse over the "Output to" option. From the menu that appears, select the monitor option without the check next to it. For laptops, there is a "Notebook" option and a "Monitor" option; select the "Monitor" option to display your computer on your TV.