Hi Wagner, the demo site is working correctly, check http://demos.hellothemes.com/hellosimple/
Did you modify something in the statick block of the slider?, or in your styles.css?. Would be better if you can tell us your url, to check the issue.
Hello, i checked your site in IE and i could see the issue, it’s rare because the demo works correclty. Send to support at hellothemes dot com your admin and ftp details, so we can check for this. Thanks.