Site opens on one computer and doesn't open in another.

I have a 2 computer network, wired through a simple D-Link router. One computer is XP and the other is Vista. The both have Internet Explorer 7. I have been visiting one particular site for several months and today I started having problems.

When I use my Windows XP, my primary computer, the message "Internet Explorer cannot display the webpage" comes back, however when I use the Vista the site opens. I pinged the site and got 4 returns successfully and I also did a tracert on the site and reached the proper IP address. These are the actions I have taken on the XP so far without any results.

1. I turned off my Zone Alarm Firewall, no change.
2. I flushed and refreshed my DNS, no change
3. I deleted all sites from my Trusted and Restricted site list on Internet Explorer, no change
4. I also checked my "host" file to make sure the site didn't get in there by accident.

I am at a loss as to what could cause this. I have been visiting the site several times a day for several months as I stated above but the first time I tried today I had problems. I hope someone can offer a suggestion.

Thanks