where i can find product key for N360 internet security ........i hv cd pack of this software?

Are you asking about Norton 360,  or about N360, an Internet Security Suite based in India:
http://www.n360.in/en/home

If the latter, I doubt anyone in this forum can assist you, and would suggest you contact their phone support. Details here:
http://www.n360.in/en/customer_care

Hi,

My name is Satnam and I work for the Social Media and Community Team at Dell.

If you have purchased the Norton CD,the product keys would be available on the CD package itself .

If in case you don't have the product key available on the Norton CD package and you have purchased the Norton CD from Dell you can contact Dell customer support with the order details .      

Thanks,

Dell-Satnam S