GRANT ALL PRIVILEGES ON databasename.* TO mysqlusername@’YOURIPADDRESS’ IDENTIFIED BY ‘mysqlpassword’;
Replace databasename, mysqlusername, YOURIPADDRESS, and mysqlpassword.
Are you sure that's the only .htaccess file in the xampp folders?
.htaccess is read by the Apache web server, so the OS would not be the issue here (since i can do the same things on linux/windows)