By default OpenHoldem will store its preferences, settings and the list of last recenttly used files an Ini-Files to avoid any fingerprints in the registry.

OpenHoldem_Preferences__feel_free_to_rename_this_file_to_whatever_you_like.INI

The filename says everything: you can name this file however you want as long as there is only one such ini-file in the OpenHoldem directory. However: other applications such as OpenScrape still use the registry. So if you have installed other applications of the OpenHoldem product-suite on your casino-machine you might want to read the Chapter about uninstallation.