Hello i have already installed windows 8.1 Core single language and i want to install windows 8.1 pro but when i try to install that it wont accept my key. what should i do please help me i really need help and also suggest me a tech site or computer site where i can chat with technician and expert please help about both problems as soon as you can its an emergency i need to format my pc because my created virus is started damaging it.