Arkose: The latest version doesn't have an installer. The archive should contain a "highres" folder and a few files; simply extract everything into the main DN3D directory. If your archive program has the option, choose "extract here" rather than "extract to"; if the files all go into their own directory the HRP won't work correctly. If everything went well you should now have a "highres" folder in the DN3D directory (as well as "autoload" if you have previously run eduke32).
When you run eduke32, choose "highres" from the box at the very bottom and you're all set. The HRP has a slightly different title screen, so the change should be immediately visible. If you have already set eduke32 to skip the setup window you can change that in the config file to get it back temporarily.
Thanks for the help. I got as far as choosing "highres"...when I load it says "Unsupported OpenGL driver detected. GL modes will be unavailable."
The new menu and everything boots but the graphics aren't changed..when I fiddle with the in-game video options and switch the renderer from software to 32 bit opengl the game crashes..
Note: I'm on Windows 7 with the latest Catalyst beta drivers. Perhaps I need to use the 9.2 ones instead (I've read they work with W7)? I'd rather not switch though..