IE6 will go to any site except one?

on one machine (WinXP) that has IE6. the IE will take you to any website, except one site. the site belongs to the company I work for! the only difference I can see, is that this pc has static IP address, while other PCs that use DHCP can access that site!! I checked the HOSTS file and I did add the ip address for that site but with no luck! any ideas?