Go to phpMyAdmin in your hosting control panel and export the whole database for the site, as a backup in case of errors. Then zip up and save your ow_userfiles folder. If you installed via Softaculous make a backup of the whole site, just in case you make a mistake. If you installed manually, just zip up the whole site, folders and files and save it.
Make your fresh install anywhere in a folder under the public_html folder, not in the existing site location. Install all the plugins and themes you had in your original installation. Unzip the copy of ow_userfiles into the new ow_userfiles folder.
Put your old site into maintenance mode. go to ow_includes/config.php and copy your database details. Transfer them to ow_includes/config.php in the new install. Also copy the site URL from that file, but don't transfer that (needed later). Check that the new site is working okay and tweak as required.
Once you are satisfied that the site is working. Remove the old site files and copy the new site files over. Go to ow_includes/config.php and change the site URL to the one copied from your old site.
If you have done everything correctly your mew site should be working. It may take a while for cached files to catch up.
If things go wrong, you can restore the old site from the backup you made.