My EE-powered site is generating a “No input file specified.” error whenever any user tries to navigate to anything other than the main page. This main page has dynamic content, all of which is being displayed. However, that content is cached by EE, so something may well be Very Wrong.
I don’t know what version I’m running because I can’t get to the CP. I last updated approx. 6 months ago (version 1.x).
I have made no significant changes to this installation in months.
How can I troubleshoot this issue?