Argento Default theme Checkout Page
Short header and footer layout
Short header and footer layout is used to increse conversion rate.
You can disable short header and footer using custom layout update file
<short_header_footer>
<reference name="header">
<action method="setTemplate"><template>page/html/header.phtml</template></action>
</reference>
<reference name="footer">
<action method="setTemplate"><template>page/html/footer.phtml</template></action>
</reference>
</short_header_footer>