Install works but directory just lists files

Hi,
I tried doing a quick search and I know I’ve run into this problem before but I can’t seem to remember/figure out how to fix it.

Install works fine but then if I go to my directory where WordPress should be running all I get is a list of the files in that directory. If I click on a file such as /wp-admin/edit.php that page will work properly, I can access all of my dashboard and add/edit posts and pages.

Thanks in advance,
jshels