How to Solve Port 80 Problems When Running Apache on Windows

There are a number of well-known Windows programs which use port 80:
IIS
The most likely culprit is Microsoft Internet Information Server. You can stop the service from the command line on Windows 7/Vista:

net stop was /y

or XP:

net stop iisadmin /y

SQL Server Reporting Services
SSRS can remain active even if you uninstall SQL Server. To stop the service:

1. Open SQL Server Configuration Manager.
2. Select “SQL Server Services” in the left-hand pane.
3. Double-click “SQL Server Reporting Services”.
4. Hit Stop.
5. Switch to the Service tab and set the Start Mode to “Manual”.

Skype
Irritatingly, Skype can switch to port 80. To disable it, select Tools > Options > Advanced > Connection then uncheck “Use port 80 and 443 as alternatives for incoming connections”.

What’s Using Port 80?

Further detective work is necessary if IIS, SSRS and Skype are not to blame. Enter the following on the command line:

netstat -ao

The active TCP addresses and ports will be listed — locate the line with local address “0.0.0.0:80″ and note the PID value.
Now right-click the task bar and select Start Task Manager. Navigate to the Processes tab and, if necessary, click View > Select Columns… to ensure “PID (Process Identifier)” is checked. You can now locate the PID you noted above. The description and properties should help you determine which application is using the port.
The Task Manager allows you to kill the process, but be a little wary about doing that — especially if it’s “NT Kernel & System”.

Microsoft-HTTPAPI/2.0

NT Kernel & System is an essential service. Stopping it will probably stop Windows in a blue-screeny-like way. Therefore, enter the following at the command line:

telnet 127.0.0.1 80

If you’re faced with a blank screen, type “GET” and hit return. The chances are, you’ll see a line stating that Microsoft-HTTPAPI/2.0 is listening on port 80. If that’s the case, open Services from Administrative Tools and locate “Web Deployment Agent Service”. Stop the service and set it’s startup type to “Manual”.
The Web Deployment Agent Service is deployed with WebMatrix and was the cause of my woes. It may also be distributed with other applications installed using Microsoft’s Web Platform Installer.
That caused me a few frustrating hours so I hope it solves your Apache or WAMP start-up problems.