My SIL has been given a very old Dell Latitude D610.
It had Win XP 32 Bit on it.
I have re-installed it to Win7 32 Bit.
Come to enter the product key I tried the one on the label on the laptop but said it was not valid

so I ended up using my product key off the install disk (which is used on anther laptop of mine

).
I am not going to register it with my product key on it.
Does anyone know how I can use the product key that is on the laptop. ?