Access to Apache in XAMPP

[MaheshNP]

When I try to click on start it shows me this error every time. I tried to uninstall few applications to clear the port but it still keeps popping up when I try to start it.
The error message is like this:
[Apache] Error: Apache shutdown unexpectedly.
6:56:16 PM [Apache] This may be due to a blocked port, missing dependencies,
6:56:16 PM [Apache] improper privileges, a crash, or a shutdown by another method.
6:56:16 PM [Apache] Press the Logs button to view error logs and check
6:56:16 PM [Apache] the Windows Event Viewer for more clues
6:56:16 PM [Apache] If you need more help, copy and post this
6:56:16 PM [Apache] entire log window on the forums
6:56:40 PM [Apache] Problem detected!
6:56:40 PM [Apache] Port 80 in use by "Unable to open process" with PID 4!
6:56:40 PM [Apache] Apache WILL NOT start without the configured ports free!
6:56:40 PM [Apache] You need to uninstall/disable/reconfigure the blocking application
6:56:40 PM [Apache] or reconfigure Apache and the Control Panel to listen on a different port

I want to know what should I do to start my apache PIDs.

[Nobbie]

Enter "Port 80 in use by "Unable to open process" with PID 4!" into Google and/or read in this forum the first (sticky) posting "Apache wont start".