I was having a problem with an aspect of Ubuntu a couple of months ago, and inadvertently enabled a different server module (or something) that overrode my LAMPP installation. The result is that I no longer have access to localhost through LAMPP, and therefore no longer can develop locally.
When I issue the '/lampp lampp start' command I get the message that the server is already running.
When I go to http://localhost/
I get the browser rendered message "It works!"
When I click on "http://localhost/mywebsite" I get a 404 not found message "The requested URL /mysite was not found on this server. Apache/2.2.12 (Ubuntu) Server at localhost Port 80."
How can I "undo" this mess? Yikes! Please help me.