Warning: mysql_fetch_object(): supplied argument is not a valid MySQL result

I have tried for days to correct this issue after cleaning up being hacked. I didn’t want to post this because I didn’t want to duplicate but found nothing that helped, so here goes:

Warning: mysql_fetch_object(): supplied argument is not a valid MySQL result resource in /home/aielance/public_html/wp-content/themes/american/header.php on line 171

</div>
  <div class="banner_bg">
<!--    <div id="example">
      <div id="slider">
        <div class="slides_container" >-->
		<div id="wrapper">
         <div class="slider-wrapper theme-default">
            <div id="slider" class="nivoSlider">
<?php
$result=mysql_query("select * from wp_slide order by id desc");
while($obja=mysql_fetch_object($result))
{
?>
<img src="<?php echo site_url(); ?>/wp-content/uploads/slides/<?=$obja->large_image?>" />
<?php } ?>
        </div>
      </div>
    </div>
  </div>
</div>

site is https://www.aidomains.net and line 171 is while($obja=mysql_fetch_object($result))

Any help would be appreciated!