What's happening here is just a basic syntax error. You're missing the closing } bracket on your else statement. It should look like this:
<?php
else
{
echo 'Welcome back, '; echo $_COOKIE["user"]; echo '!';
echo
'<br><br><br>
<img src="http://i39.photobucket.com/albums/e164/wrenchweildingmaniac/demizegames.jpg"><br><br>
<marquee bgcolor=green><h1 align=center color=red>Demize Games Home page!</h1></marquee><br><br><br><br><br><h3>News</h3><br><br>
<p>Oct. 9 2006: <br>Site open and first two things put up.<br><br>
Oct. 11 2006: <br>Forum up. Mazeman updated! Download the new new version!<br><br></p>
<a href="games.html">Games</a> <a href="http://demiseforum.awardspace.com">Chatroom</a> <a href="http://demizegames.forumer.com">Forum</a>';
} ### This was missing
?>
One other thing.. It's good practice to enclose PHP code with the
<?php
//PHP CODE HERE
?>
tags and other code in the
<html>
<head><title>other code usage</title></head><body>
<p>html code here</p>
tags. This way we get the source highlighting and makes it 90% easier to read and more likely that someone will help you 🙂