Why is port 80 of PID 4 busy?

Question

CMS

I will say right away that I read this question ( toster.ru/q/222 ), but:
1. Skype is not on the machine and was not
2. MS SQL Server Reporting moved to another port
3. I installed denver - everything seemed to work, I installed IIS - stopped. I stopped IIS, removed it from the system components, stopped all services (MsDepSvc, W3SVC), but Apache did not come to life
4. In the registry, I tried to add a new value NoRun=1 in the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\HTTP branch
5. In the manager There are no devices "Http Devices"
By PID = 4 Process Explorer gave me only 1 service - smss.exe

Answer 1

Another 80 port can be occupied by a service related to multimedia sharing on the network.
It might be "Windows Media Network Share Service" but I'm not sure.
To determine, in the browser, open the localhost and see what headers come in the response. If there are additional titles, google and find the name of the service.

Answer 2

You can run netstat -nb on the command line (from under the admin) and see which process has occupied the port of interest.