Hi,
I have both HD version and original version and I would like to set the directory path to the original version one.

The first suggestion shows in Voobly Game Diagnostics Tool dialog box will be "install the compatibility patch" instead of "browse and locate the directory path" when I first install Voobly.

I wonder except for remove HD version or rename the file name, is there any way to set up the directory path manually on Voobly?

The way it works on Voobly is that you install the game and Voobly will detect the registry entries to figure out your game path. You cannot manually define the game location. That said Voobly will allow you to choose your location when the manual detection fails. In your case it has found the HD version because that's the one you got from steam. The classic version seems to be a pirated copy (judging from help room chat log).

If you wish to use the classic version instead of HD, you can either choose to uninstall HD and then install the classic version (Copying the game folder is not the same as installing). Or you could reinstall the classic version (without uninstalling HD) and then rename the HD folder to something else. This will force Voobly to re-detect your game and it should be able to spot your classic install automatically.

Side note: If you do not reinstall the classic version, you may still be able to use it (when you rename the HD directory) however, you may have issues moving forward (Example: installing custom mods). Therefore it is highly recommended that you install the game to its default directory. Also if you are to rename the HD directory, you can switch the name back to its original entry once Voobly has successfully detected the classic install.

If you have further questions, let us know and we would be happy to have them answered.