Port settings

If port 80 is already open you likely have IIS installed.  You can either remove IIS, change the port on the site, shutdown the site, or shutdown IIS.

If IIS is not installed you can find the PID of what is listening on that port by running the following command and look for the local address that ends with :80 (it could be 0.0.0.0 or the actual IP of the system preceding the port)

netstat -ano

Select allOpen in new window

You can then open task manager, and click the processes tab
Click View, Select Columns and add the PID and command line columns
Find the PID and look at the command line that was used to start it and you've found your culprit.  Get rid of them or move them to another port and Apache should be good to run on 80.

you may also have Skype enabled go to the Skype advanced options and connection and uncheck use port 80/443

Thanks for replies!

I have changed configuration of Skype to David Johnson's suggestion and restarted the system.

Following mcsween's suggestion, I get this:

Name        PID      Username        Command line
System       4         SYSTEM             (empty)

Does this tell you guys anything?

Furthermore, when XAMPP Control Panel is started, it shows:

Problem detected!
Port 80 in use by "Unable to open process" with PID 4!
Apache WILL NOT start without the configured ports free!
You need to uninstall/disable/reconfigure the blocking application
or reconfigure Apache and the Control Panel to listen on a different port

what happens when you do a http:\\localhost

It shows page can't be found

Thanks! Worked great.