You can reset your WordPress installation back to its default status using the WP Reset Plugin.
WP Reset quickly resets the site’s database to the default installation values without modifying any files. It deletes all customizations and content, or just chosen parts like theme settings. WP Reset is fast and safe to use thanks to the built-in snapshots which provide 1-click restore functionality. It has multiple fail-safe mechanisms so you can never accidentally lose data. WP Reset is extremely helpful for plugin and theme developers. It speeds up testing & debugging by providing a quick way to reset settings and re-test code. It’s the only WP development tool for non-developers.
Please do note that using this plugin to reset your WordPress installation will delete all the posts, page, comments from your site’s dashboard.
What it will not delete is the theme files, plugins and images that you have uploaded.