You need to configure both
the television's video input and
your computers video output to work together.
Start by making sure your television video input is set to use the svideo connection on the correct channel (video1, video2, etc) via the setup menu on the tv itself. Your manual should tell you how to do this. You must also know the resolutions your tv is capable of displaying and set your computers video s output resolution accordingly or you will get nothing on the screen as well. Finally, you'll need to make sure your computers video card\system is configured to actually use the tv as a monitor.
If all this sounds confusing (it's usually very simple), please post make and model of tv and video card you're using.
You didn't give us much to go on.