Website: https://bytescout.com/products/enduser/misc/xlsviewer-business.html
Download: XLSViewerBusinessLicense-4.2.5.1975.zip – mirror
The program can totally work with most common documents like XLS, XLSX and ODS. It helps open and view Excel documents and Open Office documents without any software pre-installed. Moreover, it supports export into HTML format (.html). The tool can be used for commercial purposes only.