Cross-browser compatibility - Site rendering differently in same exact browser

Is there any reason why my site would render properly in IE8, 9, and Chrome (all same versions) on my machine, and then render differently on another machine?
I have attached screenshots of a site I’m developing. These shots are from my client. In all three cases, this site renders just fine on my end using the same exact browsers.
My client also tells me that font colors are not showing up properly in the latest version of Safari, when they show up just fine on my machine.
Any direction would be very helpful. Very urgent.

[URL=“http://www.screenshots.cc/photos/original/297-3fgn3.jpg”]What it looks like in Chrome

[URL=“http://www.screenshots.cc/photos/original/298-zk6pp.jpg”]What it looks like in IE8

[URL=“http://www.screenshots.cc/photos/original/299-2qazs.jpg”]What it looks like in IE9

What it’s supposed to look like

Please post a link to the site so we can look at the code.

(why are the screen shots reduced in size?)

http://www.gaintalent.com/temp

The screenshots are reduced in size because I copied the wrong link from the screenshots site.

Chrome:http://www.screenshots.cc/original/304/ptzdc

IE8: http://www.screenshots.cc/original/303/w2xh2

IE9: http://www.screenshots.cc/show/302/gnfax

Proper Site: http://www.screenshots.cc/original/301/ker3m

Your design (especially the nav) is very tight, meaning that if font sizes are increased at all (or calculated slightly differently) the nav bar will drop and break the layout.

screenshots.cc thinks I have AdBlock on my bowser. It’s installed but disabled. No screens for me, I guess.

I’m suspicious of wordpress’ version of clearfix. It may be perfectly valid, but I’ve never seen it written that way.

.clearfix {
}
.clearfix:after {
    clear: both;
}
.clearfix:before, .clearfix:after {
    content: "";
    display: table;
}

That’s a more modern version of clearfix that’s supported by most browsers now.

Thanks, Ralph.

Here are some discussions / posts about it:

http://www.css-101.org/articles/clearfix/latest-new-clearfix-so-far.php