Go to Blog layout - add new gadget & paste these scripts in 2 diff. gadgets... this should do. :)

<script type="text/javascript">
function disableSelection(target){
if (typeof target.onselectstart!="undefined") //For IE 
    target.onselectstart=function(){return false}
else if (typeof target.style.MozUserSelect!="undefined") //For Firefox
    target.style.MozUserSelect="none"
else //All other route (For Opera)
    target.onmousedown=function(){return false}
target.style.cursor = "default"
}
 </script>
<script type="text/javascript">
   disableSelection(document.body)
</script>

*******************************************************************************

<script language="JavaScript">
<!--

var message="Function Disabled!";

///////////////////////////////////
function clickIE4(){
if (event.button==2){
alert(message);
return false;
}
}

function clickNS4(e){
if (document.layers||document.getElementById&&!document.all){
if (e.which==2||e.which==3){
alert(message);
return false;
}
}
}

if (document.layers){
document.captureEvents(Event.MOUSEDOWN);
document.onmousedown=clickNS4;
}
else if (document.all&&!document.getElementById){
document.onmousedown=clickIE4;
}

document.oncontextmenu=new Function("alert(message);return false")

// --></script>