When I built my pc I had my friends windows 7 disk that I used for my os. Couple months later I installed windows 8 for free and got a cracked permanent product key. Now the same friend gave me an extra code for windows 8.1 he got when he ordered windows 8 but the people gave him 8.1 so he gave the extra code to me. When I enter the key it says it's not valid. Do I need to actually purchase the cd now? I also have windows 8 installed on my 1tb hdd, I would want windows 8.1 to be on my ssd. What do I do?