you need to enable the external display. this can be as easy as using the function key with another key on the keyboard (it will look like a teeny monitor symbol printed on it) or you may have to go into the display preferences in order to change it (right click the desktop, click Personalize or options, depending on xp/vista, and look for the display link or tab.

Learn Digital TV: Overall speaking, digital TV is divided into three parts, one video source collection, just as with video cameras to record images; second, the video signal compression coding by line (wired or wireless) to a user's home; third signal in the user's home digital television decoder, and to reproduce to the user's eyes. Then you also must know these conception and knowledge: RCA, S-Video, VGA input, DVI input, DVD Component, YPbPr Input This is a lot of names you recognize a few? In fact, these are the video signal input interface name. In areas not open digital TV now in order to watch high-definition video only through a computer, DVD machine, EVD, etc. playback device to obtain the signal, but how to connect these devices, they use these interfaces of the above. RCA jack S-Video, Video, and DVD component YCrCb Interface RCA is the lotus socket the title, it is not specifically for what kind of interface design, both can be used in audio, but also can be used in ordinary video signal, but also DVD component (YCrCb) of the socket, but the number is three. YPrPb is a digital high definition television professional input terminals short, also known as component video, it looks very similar to DVD component, but the support of much higher resolution, DVD component only supports 480i / p. VGA (D-SUB) interface is what we commonly known as the 15-pin interface, computer monitors mostly use this interface to support the resolution is also high, but the DVI interface, and transmit digital signals compared to analog VGA signal purity on again and disadvantages, while either DVI or VGA, because of cable quantity, but can not do very long, so in the digital television also are equipped with YCrCb or YPrPb. http://www.laptop-battery-pack.co.uk