I'm currently on build 10240 and I want to do a clean installation on the 29th when Windows 10 is officially released.
I upgraded to Windows 10 via Windows 8.1 update, so will the same key I previously used to activate 8.1 now activate a fresh installation of Windows 10? Or do I have to reinstall 8.1 Pro, then upgrade again to Win10?
Most likely -- yes. As to HOW you enter that key, we don't know at present. Win10 might prompt for a key, or it may search the drives for an installed version of Win7/8/8.1.will the same key I previously used to activate 8.1 now activate a fresh installation of Windows 10?
I have never seen a Windows upgrade that directly accepted the license key from the qualifying OS to install or activate the new version. On the other hand, there has been no broadly available free upgrade before. (There have been free upgrades, but only to those who bought a PC with a qualifying OS within a limited time before the release of the new OS. That was available mainly to reduce the number of people who would put off a PC purchase while a new OS release was imminent.)
I know that if you install 10 build 10240 as an upgrade over an installed and activated 8.1, no key is needed. I haven't tried the upgrade mode where everything from 8.1 is discarded. (That'd still be an upgrade, as you would launch the 10 installer from within 8.1. I believe that if you booted the PC from media containing the installer and ran the installer from that, you'd need a key. The key may be unavailable.)
I have read claims that once you've done an initial upgrade to 10, you will be permitted to do a clean 10 install on the same machine. The details of how that would work are limited enough that I remain skeptical.
I wish that MS had had a deal similar to that for Windows 8. For a limited time in pre-release, they sold an upgrade license for $40US. That included a key, which could be used any time. Free is good, but I'd cheerfully pay $40 for a license with fewer restrictions.
First time poster. Long time lurker.
I have a surface pro 3 running 9xxx build upgraded via windows 8.1 I then updated the build to 10240 and windows remains activated. I took a risk and did a clean install of windows 10 10240 via windows esd to iso. Don't input any keys when it's asking for keys. Just hit skip. I had to skip once via the usb boot side and then another time when setting up th account. After booting to desktop, windows will automatically activate via your old keys.
I am running a clean install 10240 on my SP3 pro right now.
Good luck
[edit] I do not know if this has anything to do with the uefi bios which has the keys implemented into the bios. I know sp3 pro does it this way
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