How to activate the windows 7 operation system



I just bought a new Dell computer, and I didn’t want to Windows 7 Enterprise Key spend extra money buying office 2007 Office 2007 Standard cause I have one on my laptop, which I thought i could kind of transfer over. Except I can’t find the case it came along with! Could someone tell me how to locate Microsoft Office Professional Plus 2010 the product key from the office 2007? Thanks!