You need to adopt a scientific approach to debugging:

1. Observe
Observe precisely what the system does - just saying, "it doesn't work" helps nobody!

2. Form a Hypothesis
ie, construct a theory to explain the observed behaviour

3. Test your Hypothesis
Devise an "experiment" that will verify whether your hypothesis is correct or not:

If your hypothesis is correct, you have identified the problem, and can then work on fixing it;

If your hypothesis is not correct, you need to form another - maybe re-check your Observations

Arvind Shrivastava said:

The problem is the LED is remaining ON for indefinate period of time ...

You need to think more carefully:

Do you mean that the LED switches on correctly when the button is pressed but then never goes off?
In that case, think what could cause this; eg,

you are not correctly detecting the switch after turning the LED on;

you detect the switch OK, but your code to turn the LED off is wrong;
etc, etc,...

Or do you mean that it's on even before the button is pressed?