PHP page are turning blank and <? disappeared... in Dreamweaver

HP page are turning blank and <? disappeared...
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Hi, I am working on PHP 4 application. When I open the files, I don't see any PHP tags <? anymore. and code turns out to be really weird.
Any thoughts why it's happening?

I have attached sample code how it looks like now.
TY.

Sample code: (no php tags, no formating)
 
register_visitor_actions(new session_visitor()); $client = $cs->load(); $sql = new mysql; $ch = new client_authorization($sql, $client); //$ch->register_admin_callback(new admin_hour_submission_check_callback($sql)); //this is now defined in the privielges block $ch->display_home();

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