Update

This solution is no longer necessary. It turns out a service called BranchCache is the culprit. Disabling this service stops Windows from listening on port 80 thus allowing you to run a web server. The description for BranchCache under services.exe is ‘This service caches network content from peers on the local subnet.’

Thanks to a fellow beta tester for the latest resolution.

I’m currently beta testing the next version of Windows, Windows 7 and came across a strange issue while trying to get Apache to install and run using the default port, 80.

Running the command ‘netstat -ano’ from the command line revealed
that port 80 is being used by PID 4.

Looking up PID 4 using Power Shell and then Task Manager revealed
that PID 4 is the NT Kernel!

So Windows 7 by default appears  to be using port 80.

After a bit of hunting around the Internet and doing some research of my own I found that the service http.sys was the culprit and all I needed to do was disable it but I could not find this service listed in the Services control panel applet.

So what’s the solution?

You have to disable the http.sys service manually via the registry:

1) Launch RegEdit:

2) Go to: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\HTTP

3) Add a new DWORD (32-bit) value

4) Name it ‘NoRun’ not including the quotes

5) Double click the new property

6) In the Value data field type ’1′ not including quotes and click OK

7) Re-boot your computer

You should now find that Apache will start on port 80!