ashwani.kumar,
Thank you for contacting the Windows Genuine Advantage (WGA) program forum. Your post is out of scope for the WGA program forum as well as out of our expertise.
There is not an avenue to see or get your Product Key from a computer. There are 3rd party applications available that would allow an end user to do this. We are unable to recommend any of them since it would be against our policy. A well phrased search in your favorite search engine should provide you the appropriate means.
Thank you for visiting the WGA program forum.
Rick, MS