Windows 10: windows 10 install

I got given my old system computer from work I whiped it and put windows 10 pro on it using the product key but wanted to change it so I got a windows 7 install disc from ebay installed it and I liked windows 10 better so I tried reinstalling windows 10 and now it tells me my product key is wrong what do I do how do I fix this

:)

 

windows xp installation and dual core am

could someone please list the steps they follow to install windows with a dual core processor and windows xp service pack to. I'm reletively new to amd dual core and i feel i'm missing a step. All help will be appreciated. thanx

 

Is it time for Windows 10 already?

Here's a good step by step guide on doing a fresh install.

How to clean install Windows 10 from a USB drive - Software - Feature - HEXUS.net

 

Installing Windows 10 on New PC?

I'm going to be building a new PC on Christmas and want to install Windows 10 on it. I have Windows 10 on my current PC, which I installed upgrading from 8.1 with the files on a USB. How do I go about installing a clean copy of Windows 10 on this new PC? I think I recall something about installing it once makes Microsoft recognize your hardware, but since this will be a PC I'm not sure what steps I need to take. Do I need to go 8.1 -> 10 or is there a method of going directly to 10?