It’s obviously nightmare to new xampp user while he can’t run apache in xampp but doesn’t know what’s the wrong! It sometimes happen for skype as it’s also port 80 for incoming connection. If you run skype before xampp, skype will use port 80 for incoming connections, so port 80 gets busy. Later if you start xampp, you won’t be able to start apache is it tries to use port 80, as a result apache failed to starts. So you have to start xampp first and then skype.
This can be solve in an easy way, just go to skype topbar>Tools>Options>Advance>Connections
Now uncheck the box “Use port 80 and 443 as alternatives for incoming connections”
So now you can start anyone first !