My dear friend,
U have mentioned that u have code to disabled F5. In the same manner u write code for R button whose event code is 82.so that ur problem abt ctrl +R problem will soved.
Now ur remaining one major problem is to disable refresh button which is
immposible.it's because user cannot disble any control of browser.
<script language="javascript">
function document.onkeydown()
{
if ( event.keyCode==116 || event.keyCode==82)
{
event.keyCode = 0;
event.cancelBubble = true;
return false;
}
}
</script>