I was activated with 8.1 pro and upgraded to 10 pro (x32). Let it activate. Worked fine, but I wanted to use x64 pro, because I have an x64 system. So since it was already activated I thought I could do a clean install of the X64 and stay activated. It didn't. work. Is there any way I can activate? Or do I have to go back and install 8.1 pro x64 and do everything again?
The 32/64 bit shouldn't matter. You must have the correct Media to get the 64 bit. You probably have the 32 bit media. Just use the Microsoft tool to download a 64 bit version of the version you are eligible for.
No unfortunately I didn't. I guess I thought from everything I have read, that you wouldn't need a key/serial when reinstalling. It is working fine, just not activated. It has been 3 days since clean install.
That's weired. I upgraded win 7 x64 to win 10 x64 and then did a clean install with win 10 x86 afterwards because notebook has only 2 gb of RAM and with x86 it is faster. I did not had to enter a serial, just skipped as told in several threads here. Worked fine!
How ever you downloaded the ISO, just copy to folder on desktop, extract the ISO, and run the SETUP.EXE. This will upgrade it, report back if any problems.