You received a Microsoft Office file(word/excel/powerpoint) as a mail attachment from your friend but there is no Microsoft Office on your computer to open the file.
You have two options to view the attached Microsoft Office file: purchase Microsoft Office Software or just download free Microsoft Office document viewers.
The free Microsoft Office viewer software allows you to view and print Microsoft documents created any version of Microsoft Office between Office 2000 to Office 2007. You can also copy data from Office documents to another programs.
However, you cannot edit an open file, save a file, or create a new file.