It is not difficult to do what you want.
a)
delete this line
f_slideIn(); which you will find right in front of </script>
b) place the two scripts which I gave you in Post#2 in the <head> and <body> respectively of your page. Right after the <head> and the <body> tags.
c) change the script in the body as follows:-
Code:
<body>
<script type="text/javascript">
if (!readCookie('visitedPreviously')) {
//document.write(' Your Message Goes Here And You See It Only Once '); // comment this line out but you may care to retain it for test purposes
createCookie('visitedPreviously', 'visitedPreviously', 1); // 1 days persistence
f_slideIn(); // call the function
}