Ok let me see if i can explain this the best i can. Last winter i decided to install Win10 preview on my computer that i have hooked up to my tv as a monitor. I went through every build all the way up until its release the 29th of July. Today it went through an update and it messed the tvs audio drivers... so i decided to do a fresh install since i was having other problems.. like my desktop folder was in the downloads folder. I tried resetting it first and it ran into an error after it was almost complete. So i restarted it from the win10 usb stick that i used the win10 usb creation tool and tried to install it from the usb. All went well but now it wont activate. The computer came with Win8.1 but i dont have the product key. What can i do?? thanks