(Windows XP with 512 MB RAM): FreeOffice 2018 (last version supporting XP). It has a “Ribbon 2007-like” interface and opens .docx, .xlsx.
Designed for speed and legacy hardware, Office 2007 Lite strips away non-essential components to provide a bare-bones productivity experience. What is Office 2007 Lite? office 2007 lite
Microsoft Office 2007 Lite is a stripped-down version of the popular Microsoft Office suite, designed to provide basic productivity tools for users with limited computing resources. This paper provides an in-depth analysis of Office 2007 Lite, including its features, benefits, and limitations. (Windows XP with 512 MB RAM): FreeOffice 2018
You can legally make lite version using the original Microsoft Office 2007 installer and MSI customization tools . including its features