We have found one software suitable in our database for this conversion.
It appears that old documents from MS WordPad (.jw) are not well-supported in newer version of the program or other word processors, so jw to docx conversion may be problematic at best.
The best course of action would be to open the file on some old computer and save it in some common exchange format, such as RTF, which can be then easily opened in MS Word and saved to whatever format you desire.
JW
A jw file extension is related to the Microsoft WordPad, a word processing tool installed in early versions of Microsoft Windows.
DOCX
Files with docx file extension are documents written and saved using Microsoft Word word processor edition 2007 or later. DOCX format replaced the previously used DOC format, moving from binary files to Open XML schema-based documents. They are supported in almost every modern word-processing tools.