What you need is the Microsoft Office product key which you obviously don't have, so why don't you try freeware office alternatives?.. there are several options available but to me, nothing compares to the Kingsoft Office Suite which offers a word processor, a spreadsheet program and a presentation maker, and all are readily compatible with Microsoft Office documents, so you can open documents created in Microsoft with Kingsoft, and vice versa.
Kingsoft Office Suite Free 2013(9.1.0.4480)
http://www.kingsoftstore.com/kingsoft-office-freeware.html
Best free Microsoft Office alternatives
http://www.digitaltrends.com/computing/best-microsoft-office-alternatives/