If we can consolidate all the windows 10 install questions to this thread i can help people a lot more efficiently but lets keep it about upgrades and installs though please so i dont have to sort through other comments.
Heres a nice FAQ from winsupersite.com for the most commonly asked questions
FREE UPGRADES OR NOT
Q. Does the Windows 10 free upgrade offer only last 12 months from 29 July 2015 to 29 July 2016?
A. YES
Q. If I am still running Windows 95, Millennium (Me), XP or Vista on my computer can I get a free upgrade to Windows 10?
A. NO
Q. I have a system running Windows 7 with Service Pack 1 – am I eligible for the free Windows 10 upgrade?
A. YES
Q. I have a system running Windows 8 with the Windows 8.1 Update installed – can I get a free upgrade to Windows 10?
A. YES
Q. Can I transfer my Windows 10 installation to another computer after getting the free upgrade?
A. NO
THE INS AND OUTS OF LICENSES
Q. I have a retail license for my Windows 7 machine. As you know, I can transfer that license from one machine to another. So can I upgrade to Windows 10 for free, then transfer my Windows 7 retail license to a second machine and upgrade that one to Windows 10 too?
A. NO.
Q. Okay, how about if I have a retail license for Windows 8.1?
A. Still no.
Q. What if I bought a retail license that was purchased online or in a store - does the system upgraded to the free Windows 10 upgrade remain licensed as a retail license?
A. YES.
Q. If I purchased my copy of Windows 7 or 8/8.1 as a retail license from either a brick-and-mortar store or an online store, then I upgrade to Windows 10, can I transfer that upgrade to a new computer under the retail licensing?
A. YES
Q. If I purchase a copy of windows 7 after 29 July will I still be eligible for a free upgrade to windows 10?
A. YES. All properly licensed Windows 7 and 8.1 machines are eligible for the free upgrade until 29 July 2016.
Q. I have a laptop and own the copy of Windows 7 Ultimate that is installed on it. I need to upgrade that laptop to Windows 10. However, after the upgrade, I would like to install the Windows 7 Ultimate OS into VirtualBox along with our old Windows XP copy for demonstration purposes. Can I do that?
A. NO. Since you are using the Windows 7 Ultimate license as the base for upgrading to Windows 10 on that device the Windows 7 license is locked to that machine and is not able to be moved. What you can do is upgrade that Windows 7 Ultimate machine to Windows 10 Pro, the version it is allowed to upgrade to.
Q. I have Windows 8.1 with embedded key . If I upgrade to Windows 10 will that key be changed and no longer work for Windows 8.1 ?
A. NO. If your system has an embedded key, then it is most likely an OEM system with an OEM license of Windows 8.1. You will be able to upgrade to Windows 10 for free and the system will be a valid install of Windows 10 and activated. Note that this is just for that machine.
Q. Still me with the OEM and Windows 8.1 with the embedded key. What if I upgrade now, and let’s say 16 months from now I want to go back to Windows 8.1 --can I do that? And then back to windows 10 a few months after that? Can I go back and forth whenever I want long as its on the same PC ?
A. YES, YES and YES, although I can’t imagine any usage scenario where you’d actually want to keep flipping back and forth between two operating systems like that.
To the first YES: the ability to simply revert your upgrade from 8.1 to Windows 10 is for just 30 days. After that you can revert back but it will require a reinstall of 8.1.
To the second YES: If you do the Windows 10 upgrade in the first 12 months it will be free for the lifetime of that device so you will be able to install Windows 10 after that on that system.
ALL ABOUT OEMS
Q. Is it true that the free upgrade to Windows 10 retains the properties of the license that was on the upgraded Windows 7 or 8.1 system? In other words if I am on an OEM system, when I upgrade it with a free Windows 10 upgrade, is it still licensed as an OEM system?
A. YES
Q. I have a genuine copy of Windows 7 Professional on my laptop. I have never installed any Windows 10 build. Can I perform a clean install of Windows 10 instead of an upgrade? Does this change depending on whether I have an OEM or Retail copy? Are there any drawbacks to not performing a clean install if this is not possible?
A. YES. Microsoft has stated that a clean install will be possible on a retail or OEM copy as long as it is a genuine system.
Q. If I built my own computer and purchased an OEM license for that hardware from either a bricks-and-mortar store or an online vendor, does my OEM license transfer to the Windows 10 upgrade after 29 July 2015?
A. YES
Q. Can I transfer that OEM based Windows 10 upgrade to another computer?
A. NO
Q. In my SMB, we have almost exclusively OEM Windows 7 Pro licenses that came with the computers. These computers are joined to a domain. Do my machines get a free upgrade? How?
A. YES. As an OEM licenses, they are eligible for the free Windows 10 upgrade. You’ll have to download the ISO for installing and upgrading the operating systems, as domain joined machines will not see the "Get Windows 10" app.
Q. If I upgrade to my OEM machine to Windows 10 from Windows 7 (with Service Pack 1) or Windows 8 (with Windows 8.1 Update), what if I want to upgrade a component in my PC a few months from now? Do the Windows 7/Windows 8.1 OEM upgrade rules apply in Windows ?
A. YES. The same algorithm will be used to determine if enough hardware has changed to trigger having to re-authorize that system. Some hardware changes will not cause a system to be de-authorized and others will.
FLIPPING BETWEEN OPERATING SYSTEMS
Q. If I upgrade to the final version of Windows 10 anytime during the first year from a system with a genuine version of Windows 7 (with Service Pack 1) or Windows 8 (with Windows 8.1 Update) installed can I reinstall Windows 10?
A. YES
Q. Can I do a clean install of Windows 10 from a system with a genuine version of Windows 7 (with Service Pack 1) or Windows 8 (with Windows 8.1 Update) installed?
A. YES
Q. If I upgrade to the final version of Windows 10 anytime during the first year from a system with a non-genuine version of Windows 7 (with Service Pack 1) or Windows 8 (with Windows 8.1 Update) installed can I upgrade to Windows 10?
A. NO
Q. Do I need to use a Microsoft Account to upgrade my Windows 7 (with Service Pack 1) or Windows 8 (with windows 8.1 Update) system to Windows 10?
A. NO