As lafontma mentioned - did you get your Office 2007 Pro OEM - with your laptop (as a deal), or did you buy it seperately like a retail box?
What threw me off I guess was "Only have product key from office pro 2007 I purchased with my old laptop. ". My bad if it was an OEM copy!
However I can reccomend a free office suite if you would like:http://www.libreoffice.org/
It doesn't look as slick as office 2007 or 2010, but it gets the job done, for free I may add.
You should be able to do a system restore with your old laptop to get your 2007 pro back as well.