Remove swfobject.js in wp_head()

if you have unwanted javascript on your page, it usually comes from plugins. deactivate them, and see if the javascript is still there.
if it still is, try updating wordpress, or switching to another theme.
if not, activate the plugins one by one, and check which one is putting this script to your head.
after finding the plugin, decide if you need it, and if you do, search the source of the plugin to find out the handle for the javascript ressource.
afterwards you can deregister the script in your functions.php.

okay, so my last option would be this:

wp_dequeue_script( 'swfobject' );

previously, you just deregistered the script, i don’t know if it stays enqueued in this case.