By "losing free upgrade offer" was that time range up to July 2016. I don't believe HWID is my case. This is a white box. The key was a perpetual key acquired via Dreamspark, Win 7 Pro. The upgrade itself is done. Win 10 is up and running no problem. The only problem is that I wanted that it to see the previous activation as valid...
Upgrading from an activated 7 will give a HWID aka Digital License for 10 on that hardware. When re-installing 10 just don't enter any keys and connect to the internet to let it connect to the HWID servers to activate. Please post the outcome of: slmgr /dlv
You can actually just activate it using your WIn7 key. I've done it with fresh installs on a dozen machines. It worked as of last week.
Install Windows Version of the legit Product Key and activate it as such, means for Windows 7 and 8.1 (could use P-Key of 8.0 and/or 8.1) start the Update to Windows 10 from within running Windows 7/8.1 and don't enter any P-Key if asked for one! After the install is done, have the computer connected to the Internet, restart and Windows 10 will be activated without question asked! Done, finish! I have done that the last time 2 days ago!
If I have Windows 7 activated by BIOS SLIC, upgrade it to W10, get free HWID, and then remove the SLIC from BIOS, will missing SLIC impact on my W10 activation?