First of all thanks for the info, actually i have done my Windows 8.1pro update & mange to submit the reservation for Windows 10, i also had received email from MS for the reservation confirmation. However after that process i'm changing my hardware (GPU & adding a sound card) & format my pc, i did the fresh installation of he Windows again, i have done all the Windows update again now the small windows upgrade logo (GWX) didn't appeared anymore, my C: drive also don't have downloaded Windows 10 file folder  , not sure it is related to the new hardware?

First of all thanks for the info, actually i have done my Windows 8.1pro update & mange to submit the reservation for Windows 10, i also had received email from MS for the reservation confirmation. However after that process i'm changing my hardware (GPU & adding a sound card) & format my pc, i did the fresh installation of he Windows again, i have done all the Windows update again now the small windows upgrade logo (GWX) didn't appeared anymore, my C: drive also don't have downloaded Windows 10 file folder  , not sure it is related to the new hardware?

don't worry, as long as the os is activated, you can use the iso to do upgrade.

just make sure the computer is connected to the internet during upgrade. ms will collect necessary information about your computer for w10 activation, so it needs a working internet connection.

i think only changing a major part like motherboard and hard disk (from my own experience) will alter the HardwareID and make the key not working. 

So your fresh install Windows 8.1 pro and activated successfully?  If yes, then you should just download and apply all the windows update and wait for the logo to appear. 

my win 8.1 pro its already activated last year never do format
but i want win 10 for to do format ssd again clean
i can burn dvd iso win 10

i think only changing a major part like motherboard and hard disk (from my own experience) will alter the HardwareID and make the key not working. 

So your fresh install Windows 8.1 pro and activated successfully?  If yes, then you should just download and apply all the windows update and wait for the logo to appear. 

my bro pc windows 8.1 pro

if i download ISO WINDOWS 10 how i get windows 10 pro select or auto select

how about product key
i have windows 8.1 pro 64bit product key

urgent

we know what you want.    but to have a working activation for Windows 10, you need to follow what me and horns suggest.

1.  Do upgrade from existing activated Win7 or 8.
2.  Make sure the upgrade Windows 10 is activated.
3.  Do a clean install (wipe clean clean your SSD in the process) for Windows 10 again.
4.  Your Windows 10 should be auto activated now.

If you are using Pro version, it will remain Pro version, same for Home version.

Bro, so the process doesn't require keying any Product key at all ?

Because what I know is some desktop pre-installed with Windows 8.1 right now, those product key embedded in their motherboard.
So when you install the windows, it will detect the motherboard hence, the windows will get activated once finish install.

That's what happen to my current desktop.

But my laptop, I normally need to key windows 8.1 key whenever I finish install windows 8.1

Yes, it will prompt you for product key but if you are upgrading from an activated windows, you can just skip the product key section.  After the successful installation, it will auto activate your new Windows 10.

The version will be the same as your current windows 8.1 - Pro will get Pro back and Home will get Home (info from one the Microsoft technical blog but i myself not tested it yet).

Bro, so the process doesn't require keying any Product key at all ?

Because what I know is some desktop pre-installed with Windows 8.1 right now, those product key embedded in their motherboard.
So when you install the windows, it will detect the motherboard hence, the windows will get activated once finish install.

That's what happen to my current desktop.

But my laptop, I normally need to key windows 8.1 key whenever I finish install windows 8.1

So there is a button for skip this round eh?

Windows 8.1 doesn't have so normally i need to use generic key to bypass 

WTA

if upgrade to win 10 and change the proc and mobo, do i need to resintall or refresh back the win 10?

btw my win 8.1 is retail version

The version will be the same as your current windows 8.1 - Pro will get Pro back and Home will get Home (info from one the Microsoft technical blog but i myself not tested it yet).

i think upgrade use refresh.

if use usb flash, then no need, cause will format as part of the process :}

I reserved the upgrade for my win8.1 pro tablet. Problem is, it doesn't have enough free space for the upgrade to download. <300mb left on primary ssd.

In this case, how do I upgrade it? Wait for MS to release ISO and via USB installer?