Ok... Thaks. I did activate the "spare" Acer laptop.
And the failing one was a dv6000 HP, I tried to resolder the graphic chip and... it worked.
So one day or another I'll have to unregister the Acer.
Or buy another licence, I'm a computer "dépanneur" and I play with lots of laptop in my home, so 2*3 is not that much