The discussion centers around finding free software for editing PDF files on Windows XP, focusing on basic functionalities like adding, removing, reordering, resizing pages, and managing bookmarks. Users recommend several tools, including PDFHammer, BeCyPDFMetaEdit, BeCyPDFAsm, and mbtPdfAsm, which offer various features for PDF manipulation, including bookmarks. A user also inquires about adding clickable links within the document, particularly for creating an interactive index. Infix is mentioned as a newer option that users find appealing. Additionally, Classic PDF Editor is highlighted as user-friendly and compatible with multiple Windows versions, with a link provided for downloading. Overall, the thread provides a range of suggestions for basic PDF editing needs on older systems.