I think that's the default html-file for new installations.
Edit: See http://world.episerver.com/Forum/Developer-forum/EPiServer-CMS-6-CTP-2/Thread-Container/2012/4/Message-This-installation-contains-only-core-files/
Thank you Mathias for the link, but how do I serve the aspx instead of the .html file?
Check the website in the IIS, under the IIS heading-->Default Document, that's the order of the default documents. Or just delete the html file as you probably won't need it.
Thank you once more for your reply Mathias!
Moved the aspx file to the top and still the same problem, do you have any other suggestions?
This message usually happens if you haven't defined a start page id. In default installations with no templates (e.g. if you select not to install the Alloy demo templates, pageStartId willl be set to "0".
<sites><site><sitesettings pageStartId="(your start page id)"...>
Thank you Arild, got to the login window!
Getting this "This installation contains only core files" while trying to enter the site. The problem might have something to do with me trying to run Episerver on my computer and not a dedicated server?