Blank hotel & self-updating script

So I've been doing retro hotels for a year now, but I've never experienced this before. I moved all my files into htdocs, but when I access localhost, it's just a blank page.
Does anyone know what makes this happen?
Attachment 161082
I have another question too, I intend to create a script that will record how many we have managed to be at the hotel at once.
I was going to use something similar this:

Code:

IF ONLINE_RECORD < USER_ONLINE THEN UPDATE ONLINE_RECORD WITH USER_ONLINE

The question is how I can get this script to update itself.

Regards Marcus