Microsoft Office Viewer
You wanted to use OpenOffice but you are not sure how your document will look like on Microsoft Office (but without buying Microsoft Office)? You can use Microsoft Office Viewer from Microsoft, for free. Since the download location is constantly changing, just search for "microsoft word viewer" (replace word with excel, power point or visio, according to your need.
Office Viewer on Linux
You can run Microsoft Office viewer on Linux using Wine (you don't have to own Windows), but currently only Excel, Word, and Powerpoint viewer that works, and only for the 97 Version (not the 2003 version). Microsoft has removed the office viewer 97 on their website and replace them with 2003 version, so you must try to search for the old version on the Net