Have you ever had the problem experience when using XAMPP whereas your installation was running smoothly. But when you run XAMPP Control Panel and start Apache web server, it said:
Possible problem detected: Port 80 in use by “system”!
Open the “Services.msc” application. Click Windows Logo, then go to run box (on Win 9x and Win XP) or go to Search Program and Files (on Win Vista and Win 7), then types: services.msc and Enter
Services Panel will appears, and fine World Wide Web Publishing Service on the list (usually at the bottom of services list, see selected service below).
If Status of WWW Publishing Service is Started and Startup Type is Automatic. Then please open WWW Publishing Service by double click at the selected service, and the Service Properties box will appears.
Please set startup type become Manual and Stop the service :
Then check the Services Panel, it should be like this: (whereas WWW Publishing Service status is blank (Stop) and Startup type is Manual)
Lastly, try to start Apache service again! It should be running smoothly.
…and Wattaaa… your web service at localhost is running :)