My hp laptop is not working properly it's telling that your window is not genuine
Did Windows 7 come preinstalled on your HP when it left the factory years ago?
If so:
The COA sticker, which has the Product Key on it, is either on the underside of the Laptop or in the Battery Compartment.
With a Desktop it is either on the side, rear or top of the Computer Case.

"How to Activate Windows 7 by Phone"
http://www.sevenforums.com/tutorials/18715-activate-windows-7-phone.html