Hi BalajiKoneti,
Your PSU will most likely not be able to run the 9600GT because it is recommended to have at least a 350w PSU by some manufacture, but it still might be able to but it will be a close call. Take a look at the power consumption Tom's HW got in their testing: http://www.tomshardware.com/reviews/nvidia-geforce-9600-gt,1780-18.html. To make this simple and short, check and see if your PSU has a connector shaped like this:
And still post your system specifications as well as the brand/model/wattage/+12v rail amps, and we can give you a definitive answer.