Ok, a few things up front before we can start debugging properly:
Your JavaScript file isn't being included right now:
standard_service_form.html : Line 10
<script src="[COLOR="#FF0000"]/JS/[/COLOR]service_js.js"></script>
standard_service_form.html : Line 11
<form method="post" action="contact.php" [COLOR="#FF0000"]onsubmit="return CheckForm();"[/COLOR]>
standard_service_form.html : Line 522
[COLOR="#FF0000"]<input type="submit" value="Submit Form" />[/COLOR]
(you can put the thank you message in the script file instead)
Remember, depending on your host, case-sensitivity is also important so watch how you name files/folders. I typically just keep everything lowercase to avoid problems.
Once we have those corrections done at least then we can look at how the validation script works 
Wow, I just realised your [FONT=Courier New]<form>[/FONT] is sitting in the [FONT=Courier New]<head>[/FONT], it should be moved inside the [FONT=Courier New]<body>[/FONT] tag. And the <form> is being closed prematurely after the Personal Info section, that should be removed.
