Hi
I have just purchased a new laptop running Windows 10. I already have a copy of Office 2010 so tried to load onto my new laptop. (I Deleted it from the old Dell)

At the very start it asks for the product key. It was acceptable and 2010 loaded.
However when I tried to register Office on line I was told it was not a valid key.
The only option I was given was a 5 day trial.
As I had to look at a couple of important documents in the end I clicked on the 5 day trial.
HOW can I get Office 2010 loaded, LEGALLY ??
Thanx in advance