Linked files and folders in Windows Vista

Open the Control Panel, and click 'Classic View' on the left sidebar.

Open 'Folder Options'

Click the 'View' tab and scroll down to 'Managing pairs of Web pages and folders'

Choose 'Show and manage the pair as a single file' Now Explorer will only show page.htm and treat both the file and the folder as one file.

Or, choose 'Show both parts and manage them individually' and Explorer will treat them as plain old page.htm and page_files.

Although this feature (called "Connected Files") may be considered a nuisance (especially if not expected), it can be useful in some contexts. It is documented by Microsoft here:Managing the File System - Connected Files

(Thanks to Anders on StackExchange Aug 10 '17 at 17:57)