I have this very old Nextbook tablet given to me by my cousin. The original OS installed was Windows 8. There was a issue with the batteries so I somehow got the battery replaced. I had to reinstall Windows 8 but as I didn’t have the product key windows could not be activated.
It has an Atom processor. Can I install Home assistant OS on it or any other OS so that I can use it as a screen for Homeassistant.
If you want to use it as a screen for controlling HA, installing HAOS will not help you. Try searching for kiosk mode on the forums and you’ll likely find some info on this.
For W10/11 you don’t need a key anymore (but the free version will have a few restrictions).
But why not go for a linux distribution? They are all for free 
Ofc you van also install HAOS, but the machine has to be able to boot from UEFI (check bios)
But…HAOS will only give you HA, nothing else…
I will install Linux mint and check it out. Hopefully browser should work as a touchscreen tablet
I loaded Linux mint. The installation went fine without errors. But it was not booting. Something went wrong with Grub installation.
Is there any other OS supporting touchscreen or where I just get the browser working for homeassistant dashboard.
Twice I tried installing Linux Mint.