Nitish, does your computer have an "S Video" output? If so, connect the S-Video directly to the TV S-Video input. If not, here is some information for a card that will give you an S-Video output from your computer. http://askbobrankin.com/tv_as_computer_monitor.html
This article explains the downsides of trying to use a TV as a computer monitor - http://www.howtodothings.com/electronics/a3543-how-to-use-your-tv-as-a-computer-monitor.html
Remember what I said about the resolution.
Here is a video that explains some of this - http://www.youtube.com/watch?v=llxbE8f52Pc
Another useful video - http://www.youtube.com/watch?v=g2ZBO4kQqxw&feature=related