Alright, from your logs, it shows that you have a “problem” in your xampp configuration. Specifically mysql/mariadb configuration.
The MariaDB server is running with the --skip-grant-tables option so it cannot execute this statement in C:\\xampp\\htdocs\\openemr7\\library\\classes\\Installer.class.php:1288\nStack trace:\n#0 C:\\xampp\\htdocs\\openemr7\\library\\classes\\Installer.class.php(1288): mysqli_query(Object(mysqli), 'CREATE USER 'op...')\n#1 C:\\xampp\\htdocs\\openemr7\\library\\classes\\Installer.class.php(243): Installer->execute_sql('CREATE USER 'op...')\n#2 C:\\xampp\\htdocs\\openemr7\\setup.php(1143): Installer->create_database_user()\n#3 {main}\n thrown in C:\\xampp\\htdocs\\openemr7\\library\\classes\\Installer.class.php on line 1288, referer: http://localhost/openemr7/setup.php?site=default
So you may start resolving your issues from this angle.
check these solutions here
stackoverflow
grepper