Hi, so my computer had a problem and the only way for me to repair it was to format it. I thougth that it would be a great idea to wait till the release of Windows 10 to do it since I would have formated it anyway. I installed Windows 10 using a bootable usb that I made from my other computer. My problem is that I can't activate my Windows 10 even with the serial key from the computer (with win 8.1 and I reserved Win 10 with it). I don't know what to do.