Hello and welcome to Tom's Hardware Forums.
MS Office is a paid-for product and any free copy someone offers you will probably not work or activate. There is a free alternative - Google for Open Office and follow the links. I t works with existing documents and spreadsheets and wil create new ones in the same way MS Office does.
Because Microsoft likes to catch young folks for life, there is a very inexpensive deal on MS Office for students if you look around.
Thanks for discouraging piracy! It is not only unfair to the developers, but it takes a huge toll on our economy. Take it one step further and spread the word that people can help curb this issue by reporting corporate software piracy to the BSA: http://nopiracy.net/ZCB0LL