free office suites like openoffice.org, libreoffice are free and fully featured. moreover, you won't have to face hassle like serials/keys/activation etc. i've used both libreoffice and openoffice, both are great. viva freeware!
libreoffice windows version download link: http://www.libreoffice.org/download/?nodetect
just in case, openoffice.org recently changed its name to apacheopenoffice. site address is still same though. http://www.openoffice.org/download/index.html