How Google Adsense Detects Invalid Clicks?

[seoexpert]

i dont think Google 's cookies will remain in a computer for 10 years it has no logic how can a cookie will remain in a pc if some body delete from registry or hard disk mainly google has Ip detection technique which is very powerful and they track by this.

You are absolutely right, its a absurd thing, a cookie stored in ur client side and it has many merits and demerits also but no cookies will stored in ur system for such long time, its beyond the logic and its the the real fact and there are many gadgets, software and scripts available with google by the help of them they can easily track the activities of your site and can detect the fraud click.These cookies helps them partially not fully.
Thanks.