I've been trying on clean copy to minimize my errors first, I'm not modifying an installation, right now just trying to add the PID to bypass OEM error to get it work on the obsolete laptop.
Also trying to copy clean Windows 7 iso and didn't boot.
Now I've tried this:
Imgburn> (Working windows 8 bootable disc) > Copy image.
Imgburn> Blank DVD > Burn the image > I get "Disc need formating" and it's stuck on 99%.
Used Nero to burn that exact image on the same disc, burned successfully and booted to windows setup.
Must be something with Imgburn, it hasn't been updated since 2013, so that's most likely why.
Now the DVD RW is corrupted and unusable after being burned with Imgburn, great, total waste of 13 DVDs.
I've the original iso's burned on discs from back then.
The original iso can burned with any tool and it is bootable, it looses the bootable feature once the iso has been extracted (to my know).
Thank you for trying to help me on this.
As I was writing, finished burning another clean copy of windows 7 and failed to boot.
Used Imgburn to verify Disc with Iso image, I got +99 miscompare (errors in sectors)
So my guess is Imgburn is bad with newer hardware.
I'll find another way.
Thanks again.