Unable to Start Web Site on IIS – “Process can not access the file because It’s being used by another process”. How to resolve ?

I was trying to run one of my local IIS hosted site I got page not found error. I was quite surprised to see that error because the site was up and running few hours back. I opened the IIS and found that my Site Application was in stopped mode. I started the web application and got the error message displayed below

Problem : Error message “Process can not access the file because It’s being used by anther process”  while starting the web application from IIS.

Investigation and Resolution:  Earlier my web site was running on the default IIS port ( Port 80 ).  From the error message it’s clear that port 80 is being used by some other process or some one is blocking it.

I changed the default web site port which was 80 to some unused port (8087). To achieve this right click the application and then click Edit Binding.

After this port change I started the site again and it started.  So, the main problem as identified was Port 80 being used by some other process.

I have already discussed the resolution process, which is to change the port. But, I want to my Site to run on Port 80, so I have to identify which process is blocking the IIS Port 80. To check this I used netstat command which displays the details of port along with the process ID.

I found that Process ID with 3368 is blocking the port 80. I opened the Task manager and added the Process ID Column from setting and found one of my chatting application using the Port 80 😦 .