HP: http://www.mtexplorer.com/mtExplorer is a minimalist multi-pane file explorer. I have tried quite a number of dual-pane and tabbed file explorers, but none of them could give me 4 to 6 Explorer panes simultaneously in a single window.
So I wrote mtExplorer, which can be configured to display 1, 2, 3, 4 or 6 Explorer panes at once. You can drag-and-drop files between panes easily. There are no menus, status bars or fancy toolbars to get in the way. Buttons are kept to a minimum. The right-click context menu is used to perform most operations.
mtExplorer consists simply of a small executable file. Settings are written to an INI file in the same folder as the EXE file. No installation is required. You should be able to run it from any folder, or pop it into a USB memory stick and run it on any Windows PC.