I have a laptop which has Genuine 7 home basic 64 bit installed. I am looking forward to buy Home Basic to Home Premium Upgrade license as it's cheaper than retail version. What I have learn so far is, I can only use Upgrade key on an existing genuine windows 7 installation. So, that means, if in future I face the need to format my laptop I will have to install the home basic first then follow the procedure to perform basic to premium upgrade. Right? Okay is there a way out that would allow me to install Home premium directly using the upgrade license? And is it going to make my OS illegal?