I have a machine running Server 2008 / IIS 7.0. The machine is equipped with two separate NIC's with two distinct IP addresses (10.1.1.179 and 10.1.1.180). I have a WebMail client program running on 10.1.1.180 and it is bound only to that address. When I try and start a website from within IIS7, I get the "Process cannot access the file because it is being used by another process 0x80070020 error" I have checked and the IIS site is bound to the other IP address (10.1.1.179:80). When I run a NETSTAT -an it shows the WebMail site listening on 10.1.1.180:80 and nothing listening on the other address the IIS site is bound to (10.1.1.179:80). If I stop the WebMail client, the IIS site starts no problem... If I change the IIS port from 80 to 8080 it runs fine with the WebMail client.... How else can I find out what program or application has locked up 10.1.1.179:80 (the IIS NIC)?