we need more info

are you able to watch on your lap top without the TV?

also you will need to run a Audio line as well as the VGA line

right click the mouse and you will see graphic properties

you can select monitor from there and that should bring it up on your TV

but as I said if you want the sound through a separate audio line from the head phone socket to your TV input audio socket

yet me know how you go 

Most laptops will have a sort of shortcut key.  Look among the Function keys (F1, F2, etc).  There should be one with an extra marking that looks like laptop and a TV screen.  For my old Dell laptop, it's F8.  So I press the Fn button (lower left of keyboard, between the L-ctrl and Windows keys) and F8 simultaneously.  This cycles between laptop display, TV display, or display both.  Make sure your TV is turned on and set to the correct input channel for PC or VGA.

Alternatively, you can dive into the graphics option menu....

It could be a plethora of issues.  

Does your old laptop run a different operating system and graphics software?

Your best best it to have an HDMI  laptop...thats all I have used for 2 years.

It is mostly likely the graphics card (or integrated one) on your old laptop that is giving you issues.

Pretty much the hardware is broken or one of the chords doesn't work. You can check to make sure all the circuits are running properly. The best way to do this is to get it tested at a local computer store. They should know how to diagnose the problem. It's too hard to diagnose the problem if it's not visibly in front of me.

It could also be the brand of laptop you are using.  I know for example, that my Sony laptop does not do video out, only video in.  The best thing to do would be to google "X brand laptop video out" and you will be able to find your answer pretty quick.