In the comments for the General Knowledgebase download at GOTD, a few commenters mentioned this software: Remlap Knowledgebase. It's at http://www.remlapsoftware.com/ Here's part of the summary from the developer:

> From study notes to course-work, research notes, personal information and spreadsheets, all can be managed efficiently, easily and securely. Just about anything can be stored within a KnowledgeBASE Document, including text, pictures, spreadsheets, Graphs and Charts.
... there are no confusing data-trees to work your way through. Instead, more closely mapping the way we think, KnowledgeBASE utilizes a Keyword Indexing system, which is more powerful and more flexible.

Doesn't appear to install on Vista :(