Spry Menu Bar wraps to second line on a few monitors

Question

Hello-
I am stuck on a spry horizontal menu bar and have discussed with a few local dreamweaver users and we can't figure this out. I'm using CS4 to create an internal site for my company (sorry, I can't send you link). I tested the site on firefox and explorer on my computer and everything works beautifully. When going through the soft launch one computer out of the six computers who reviewed the site had an issue with my navigation bar. I used the horizontal spry menu bar to create a navigation with six options. The problem computer wrapped the last two to a second line which makes everything weird on pages within the site.
Screen captures are below. Three images show the main page where the navigation wraps on top of the side column and right column. The second image shows the menu bar wrapping behind the left column on additional site pages which is happening on all additional site pages.
The code for the spry menu assets should be below the images. If you need additional information, if I didn't provide everything, I'll send it. I'm very new to this and pretty much self-taught. I have taken an online class through ed2go.com, I've asked a ton of questions from other designers using Dreamweaver, and I've watched MANY tutorials online. ANY help you can give would be MUCH appreciated. THANK YOU!!
MAIN PAGE/HOME PAGE
ADDITIONAL SITE PAGES
@charset "UTF-8";
/* SpryMenuBarHorizontal.css - version 0.6 - Spry Pre-Release 1.6.1 */
/* Copyright (c) 2006. Adobe Systems Incorporated. All rights reserved. */
LAYOUT INFORMATION: describes box model, positioning, z-order
/* The outermost container of the Menu Bar, an auto width box with no margin or padding */
ul.MenuBarHorizontal
margin: 0;
padding: 0;
list-style-type: none;
font-size: 100%;
cursor: default;
width: auto;
background-color: #D6D6D6;
background-image: url(/Images/Autry_Background.jpg);
/* Set the active Menu Bar with this class, currently setting z-index to accomodate IE rendering bug: http://therealcrisp.xs4all.nl/meuk/IE-zindexbug.html */
ul.MenuBarActive
z-index: 1000;
/* Menu item containers, position children relative to this container and are a fixed width */
ul.MenuBarHorizontal li
margin: 0;
padding: 0;
list-style-type: none;
font-size: 100%;
position: relative;
text-align: left;
cursor: pointer;
width: 8em;
float: left;
/* Submenus should appear below their parent (top: 0) with a higher z-index, but they are initially off the left side of the screen (-1000em) */
ul.MenuBarHorizontal ul
margin: 0;
padding: 0;
list-style-type: none;
font-size: 100%;
z-index: 1020;
cursor: default;
width: 8.2em;
position: absolute;
left: -1000em;
background-image: url(/Images/Autry_Background.jpg);
/* Submenu that is showing with class designation MenuBarSubmenuVisible, we set left to auto so it comes onto the screen below its parent menu item */
ul.MenuBarHorizontal ul.MenuBarSubmenuVisible
left: auto;
/* Menu item containers are same fixed width as parent */
ul.MenuBarHorizontal ul li
width: 8.2em;
/* Submenus should appear slightly overlapping to the right (95%) and up (-5%) */
ul.MenuBarHorizontal ul ul
position: absolute;
margin: -5% 0 0 95%;
/* Submenu that is showing with class designation MenuBarSubmenuVisible, we set left to 0 so it comes onto the screen */
ul.MenuBarHorizontal ul.MenuBarSubmenuVisible ul.MenuBarSubmenuVisible
left: auto;
top: 0;
DESIGN INFORMATION: describes color scheme, borders, fonts
/* Submenu containers have borders on all sides */
ul.MenuBarHorizontal ul
border: 1px solid #CCC;
/* Menu items are a light gray block with padding and no text decoration */
ul.MenuBarHorizontal a
display: block;
cursor: pointer;
padding: 0.5em 0.75em;
color: #FFF;
text-decoration: none;
font-family: "Trebuchet MS", Arial, Helvetica, sans-serif;
font-weight: bold;
text-align: center;
vertical-align: middle;
background-color: #005BAE;
/* Menu items that have mouse over or focus have a blue background and white text */
ul.MenuBarHorizontal a:hover, ul.MenuBarHorizontal a:focus
background-color: #CCC;
color: #000;
text-decoration: blink;
/* Menu items that are open with submenus are set to MenuBarItemHover with a blue background and white text */
ul.MenuBarHorizontal a.MenuBarItemHover, ul.MenuBarHorizontal a.MenuBarItemSubmenuHover, ul.MenuBarHorizontal a.MenuBarSubmenuVisible
background-color: #CCC;
color: #333;
SUBMENU INDICATION: styles if there is a submenu under a given menu item
/* Menu items that have a submenu have the class designation MenuBarItemSubmenu and are set to use a background image positioned on the far left (95%) and centered vertically (50%) */
ul.MenuBarHorizontal a.MenuBarItemSubmenu
background-image: url(SpryMenuBarDown.gif);
background-repeat: no-repeat;
background-position: 95% 50%;
/* Menu items that have a submenu have the class designation MenuBarItemSubmenu and are set to use a background image positioned on the far left (95%) and centered vertically (50%) */
ul.MenuBarHorizontal ul a.MenuBarItemSubmenu
background-image: url(SpryMenuBarRight.gif);
background-repeat: no-repeat;
background-position: 95% 50%;
/* Menu items that are open with submenus have the class designation MenuBarItemSubmenuHover and are set to use a "hover" background image positioned on the far left (95%) and centered vertically (50%) */
ul.MenuBarHorizontal a.MenuBarItemSubmenuHover
background-image: url(SpryMenuBarDownHover.gif);
background-repeat: no-repeat;
background-position: 95% 50%;
/* Menu items that are open with submenus have the class designation MenuBarItemSubmenuHover and are set to use a "hover" background image positioned on the far left (95%) and centered vertically (50%) */
ul.MenuBarHorizontal ul a.MenuBarItemSubmenuHover
background-image: url(SpryMenuBarRightHover.gif);
background-repeat: no-repeat;
background-position: 95% 50%;
BROWSER HACKS: the hacks below should not be changed unless you are an expert
/* HACK FOR IE: to make sure the sub menus show above form controls, we underlay each submenu with an iframe */
ul.MenuBarHorizontal iframe
position: absolute;
z-index: 1010;
filter:alpha(opacity:0.1);
/* HACK FOR IE: to stabilize appearance of menu items; the slash in float is to keep IE 5.0 from parsing */
@media screen, projection
ul.MenuBarHorizontal li.MenuBarItemIE
  display: inline;
  f\loat: left;
  background: #FFF;

Answer 1

Hi, Mel,
I see that you are using default widths for the list items in the menus. If you reduce the width of the list items, you should be able to settle on a width that works better than 8em and 8.2em.
Here are the bits that will need editing:
ul.MenuBarHorizontal li
margin: 0;
padding: 0;
list-style-type: none;
font-size: 100%;
position: relative;
text-align: left;
cursor: pointer;
width: 8em; /* make this width smaller */
float: left;
/* Submenus should appear below their parent (top: 0) with a higher z-index, but they are initially off the left side of the screen (-1000em) */
ul.MenuBarHorizontal ul
margin: 0;
padding: 0;
list-style-type: none;
font-size: 100%;
z-index: 1020;
cursor: default;
width: 8.2em; /* make this width smaller */
position: absolute;
left: -1000em;
background-image: url(/Images/Autry_Background.jpg);
/* Submenu that is showing with class designation MenuBarSubmenuVisible, we set left to auto so it comes onto the screen below its parent menu item */
ul.MenuBarHorizontal ul.MenuBarSubmenuVisible
left: auto;
/* Menu item containers are same fixed width as parent */
ul.MenuBarHorizontal ul li
width: 8.2em; /* make this width smaller */
Z