What Gombot means is a lot of the time on a website it will have specs on what is required in order to view the website ( I cant stand when it says you must use IE to view this website, Firefox fanatic here). Since other users in your office are able to open it but you cant, it may very well be your IE settings. Bring your laptop over to a desktop that can access the ESS site. On both computers, open up IE, click the tools menu, and go to internet options. In the box that pops up, go to the Advanced tab. Now compare both. You should setup your laptop identical to the desktop that can access the website. If this does not correct the issue, then you can rule out your internet options as the issue.
Gombot also makes a very good point. It could require the latest java or plug-ins such as flashplayer. Normally, a site will prompt to install an ActiveX control if needed. Sometimes, if you dont have admin priviliges on the computer, it will not prompt you and you wont be able to access the site. See if thats the case.
Again, with your laptop next to a desktop that can access the site, open up IE and click the Tools menu. Click Manage Add-ons. Make sure it says on the Show: section "Add-ons currently loaded in Internet Explorer" and compare with the working desktop. If you are missing anything than that may be the problem...