Here is some information found when googling autostart flash in IE7. Hope it helps.
https://www.kirupa.com/developer/flash8/flash_fix.htm
Also I use a java script like BrandonRandon that is Xml transitional valid that looks like this.
<script type="text/JavaScript">
<!--
function MM_openBrWindow('width=400,height=340') { //v2.0
window.open('width=400,height=340');
}
//-->
</script>
<script type="text/javascript">
AC_AX_RunContent( 'classid','CLSID:6BF52A52-394A-11d3-B153-00C04F79FAA6','width','400','height','340','class','pictureC','id','player','url','https://www.savethecolors.com/WordPress/assets/Videos2/press1forEnglish.wmv','autostart','true','controller','true' ); //end AC code
</script><noscript><object classid="CLSID:6BF52A52-394A-11d3-B153-00C04F79FAA6" width="400" height="340" class="pictureC" id="player">
<param name="url" value="https://www.savethecolors.com/WordPress/assets/Videos2/press1forEnglish.wmv" />
<param name="autostart" value="true" />
<param name="controller" value="true" />
</object></noscript>
Perhaps you could use this with a swf on page load.