respected sir,
i got a new laptop for which i used windows7 ultimate os from my friend store and it after some days of use i got it to be not a genuine one build 7601 how to get rid off it please help me it is said that genuine will cost more than 3000 inr

Well, actually you can't get genuine windows without spending money but you can use alternative of windows like Ubuntu, its the same linux which you use as Android in phones
Try Ubuntu and it 100% free to use and have lots of advance features.

And actually you are using pirated windows version and its illegal to use it.

You cannot get genuine windows without spending money. You can try to download from torrent sites which will give you a product which was already registed for one computer. So you cannot make updates with that os and several problems will arise due to hardware compatability issues.