Here’s looking at you, Office
Microsoft Office viewers are available if you don’t have Microsoft Office programs. Click here for the download page for viewers for all MS Office products, Word, Powerpoint, Excel, Outlook, Access, and Visio.
Remember: you can see the files with these viewers, but you cannot edit them in any way.
You can also use LibreOffice (freeware compatible with MS Office Suite before 2007) to view Word, Powerpoint, Excel, and Access files (before 2007) as well as edit and save them to MS Office formats such as 97-2003 formats.
Remember: you must not use 2007 formats (ending in “x” such as “.docx“) if you want to use other programs such as LibreOffice, WordPerfect, etc. to view or edit them reliably.