Your port 80 is actually used by :

Information not available (might be Skype).
Cannot install the Apache service, please stop this application and try again.

Press Enter to exit…

Look in your taskbar for Skype. You may have to click the chevron (arrow) to reveal all of the hidden icons. Even if the Skype icon is gray, the application is still running. The gray color means that you aren’t logged into the Skype servers. However, the application is still reserving port 80, which is required for running a web server. (The HTTP protocol, by default, runs on port 80.)

how to start the apache service

“could not execute menu item (internal error)”

“the service has not been started”