You can use 7zip or winrar for open rar and zip files for free.

http://www.7-zip.org/download.html
https://www.rarlab.com/download.htm

The Microsoft Office files (doc, docx, xls, xlsx, ppt, pptx, etc.) can be opened with Microsoft Word, PowerPoint, Excel etc. Go to this link to download a 60 day trial version:http://office.microsoft.com/en-us/try/
For problems regarding different versions compatibility go here: http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=3