Avishek Kc :
DookieDraws :
If you have a legit copy of Windows 8.1 Pro, then yes, you can "upgrade". Upgrading will simply overwrite your current Windows 8.1 Pro to Windows 10 Pro. After you have upgraded successfully to Windows 10 Pro and confirmed the activation worked properly, then you can download a Windows 10 Pro ISO and do a clean install if you wish.
yes i have a legit copy of windows 8.1 pro. i have reserved a copy of windows 10 pro and have received a notification in windows update to upgrade to windows 10 pro which is around 2.7 gb in size but my actual question is I ve only 16gb left in my drive so after i download windows 10 from update will i able to upgrade to win 10?
Yes. Update to Windows 10 Pro through windows update.
After you have successfully upgraded to Windows 10 Pro and confirmed it's activated, you can then download the ISO for clean installs if you wish. I would recommend updating through Windows (instead of a clean install) at first to avoid any issues with the upgrade.