Why Word won't take it directly
Microsoft Works saved documents in its own .wps format, not Word's. Microsoft once offered a Works converter for older versions of Word, but it isn't part of Word today, so current Word, Pages and Google Docs can't open a .wps file at all.
The usual way round that is an online converter, which means uploading the document to someone else's server. This page does the conversion inside your browser instead, so personal letters and records never leave your computer.
Three steps
First, drop the .wps file on the box above. The page reads it with libwps, the open-source Works reader inside LibreOffice, and shows the pages as they were laid out.
Second, look through it. The fonts are drawn with metric-compatible open fonts, so lines break where they did in Works, and you can see straight away whether anything is missing.
Third, save it. "Save as PDF" is free and keeps the look exactly. "Word file" (part of the one-time unlock) gives an editable .docx with the text, bold and italic, fonts, indents, tab stops, tables, headers and footers, footnotes and pictures.
A folder of old documents
With the unlock you can drop a whole folder, or a ZIP of one, and get back one ZIP that mirrors it: a PDF and a Word file for every document, and a list of anything that couldn't be opened, with the reason.