We know that Windows 7 is going to launch on 22nd of October, that means it’s the end of evaluation version.The exact date is 20th of August after which one may not be able to get Windows 7 downloaded. However if you have the software you may get the verification key till March 2010. To get your product key simply go to this page and follow the instructions.
If you need any installation instructions kindly check this page.The full version of this operating system is going to be launched on 22nd of October, that means the laptops and the desktops are equipped with the latest operating system from Windows after this date. However if you are planning to buy a Dell, Lenovo or HP laptop then you can buy it right now as they will upgrade your laptop for free but kindly check that free upgradation is available with your model or not as this scheme is not for every laptop from the respective company.