Hi guys.. friendly speaking, right now i'm using ehem Windows 8.1 right .. I want to buy the original key so i can upgrade to Windows 10.. so i think i dont have any problem with that..

so my question is.. lets say after a while i need to format n clean install my windows 10, can i just key in the serial no for Windows 8.1 that i bought before?

cannot. win 8.1 key is for windows 8.1 not win 10

I using ehem windows 7, i selamba go free upgrade for windows 10 , lets see how it goes.

Iinm as long as you didn't change your motherboard, you should be fine.
Windows 10 will automatically activate once you have upgrade your Windows 8.1.
Just skip if installation ask for serial number.
No problem.

Daz loader on Windows 7?

install the windows 8.1, insert the serial key that you bought before.
then download the windows 10 apps and wait for the confirmation.

read here for more details: http://www.microsoft.com/en-us/windows/windows-10-upgrade

What if I am upgrading from from retail 8.1 to 10 taking advantage of the free first year upgrade, then in year 2018, my HDD decides to die on me. How will I reinstall back win10 on my future new HDD?

By the time, I would need to enter serial number to install win10 directly through USB/DVD. Question is......which serial? Win8.1 serial?
Or the activated win10 upgrade serial? (Where do I even check my current win10 serial in first place?)

If you have activated the Windows 8 / 8.1 key at least once on your machine then you may reinstall / clean install your Windows 10 copy as many time as you want as long as you does not change your motherboard, (as it is deemed as a new machine by Microsoft).

*However changing motherboard doesn't mean your key is void, simply call Microsoft customer service, they will guide you, provided you own a retail product key (not an OEM key). I have done this with two different motherboards before.

Download the official Windows 10 .iso here
http://www.microsoft.com/en-us/software-download/windows10

You will be prompted with product key boxes during pre-installation process, but you can simply skip it. Your Windows 10 will be activated once you're online.

*Since your product info is already on Microsoft server (from your previous Windows 8.1 activation) you don't have to worry about the product key.

What kind of information?
Which 'product' info is being used to determine whether my PC is eligible for the activation?
Mainboard?HDD?SSHD?SSD?RAM?GPU?CPU?

What if I buy entirely new system in year 2018 (replacing all my components), how will I install win10 again? (Remember, currently, I have a retail win8.1 serial upgraded to free upgrade win10). How will the activation (transfering the license to new system) take place?

EDIT: For those who said the activation tied to microsoft account (MSA), sorry to said, I dont have one nor I intend to use it.

This post has been edited by JohnLai: Jul 31 2015, 11:00 AM

This is all you need to know about Windows 10 activation:
http://answers.microsoft.com/en-us/insider...2f-4b21fbd807a7

Too long to cut and paste here.

Tied to the "device". Probably this means mainboard..........so, no need to enter serial for new fresh win10 installation after upgrading from 8.1 and the win10 will auto activated after few days.

Sound easy......but....if I change mainboard (my current mainboard already 24/7 for 3 years straight), how? Call microsoft and tell them about my win8.1 serial that I use for the upgrade? After all, there isn't any win10 serial for those who choose the free upgrade route.....it not like I can use my retail win8.1 key can be used for win10 fresh install in year 2018...

As long as you passed the online genuine validation, you're good to go.

Yes, it is tied to the main board. Once you changed the main board, you'll lose the activation.

Seriously, if you built a new system why don't you fork out some more money for a new retail win 10. It'll be much cheaper 3 year from now

Your best bet it to buy a win 7 key (since it's cheaper) and upgrade.

Once you activated, the license will remain in your system forever, as long as you don't change the main board.
But remember, you need to perform an upgrade first from your win 7 system, once you've verified that your new win 10 is activated, then you can proceed to reset/clean install win 10.

I have done exactly like what you said. I reserved a free upgrade for windows 10. After upgrading to Windows 10. I found that my pc was too laggy and I decided to do a clean Windows 10 installation.

Before clean installation, I used Magical Jelly Bean Keyfinder to retrieve my Windows 10 CD Key and keep it somewhere else. I downloaded Windows 10 ISO file: https://www.microsoft.com/en-us/software-do...ad/windows10ISO

Then, made a bootable Windows 10 USB installer using Rufus.

I did a clean windows 10 installation. During the installation, I entered the windows 10 CD Key I retrieved earlier and it worked and activated.

I noticed that Windows 10 CD Key is different from the original Windows 8 CD Key which I used to upgrade to Windows 10.

your pc laggy after upgraded right? Mine too.
After troubleshooting and stuff, my system is ok. Only UI was laggy because of win 8.1 display driver are not compatible with win 10.
Update the display driver, all working fine dy..

My system got laggy because of having too much rubbish in my drive only 20%~ remaining free space.

Problem is....I am using retail 8.1 now....Microsoft said, if win8.1 retail key is used for win10 free upgrade, the retail terms and conditions will carry over to win10.

In a sense, if I change mainboard in future, I am supposed to use my free win10 activation that I got from my retail 8.1 key.

Problem is, the way people describes current win10 activation that ties to hardware IDs, I might have problem installing or getting win10 activated at my new system.

OK I get what you meant.
According to microsoft, the free upgrade version of win 10 is only for the lifetime of the device it is installed on.
So I don't think you can use the win 8.1 key again to get a free upgrade after the one year period. You also can't use the generated win 10 key as it just a generic key - a unique id of your current hardware.
I'm afraid you have no choice but to buy a new retail win 10 key.

So my advice, if you want to upgrade your PC, do it before 29 July 2016

P/s: You better call Microsoft and ask for definite answer regarding this matter

After u upgraded to windows 10, use the reset settings built into windows 10 to perform a clean install. no hassle or whatsoever, note: this feature is in windows 8.1 too