I have a drupal 4.7.3 site that has been up and running smoothly for years now, and recently, out of nowhere, I cannot login as the admin (or any user) anymore.
The login page only refreshes after submitting the form. Navigating to the admin pages only gives "Access Denied", and I've tried simple things like clearing cookies, etc. At the same time as this, the comment form also stopped working, so it looks like they're related. I have a captcha in the form, but its set to always require the same word to be typed in the field, and after submitting, I get an error indicating it is incorrect. The captcha is also something that has been up and running for years now.
All the content is accessable, as much as an unauthorized user should see, so the site is still there, I just can't get to it. It is hosted on Yahoo, and from what I can tell, they haven't discontinued support for the php or mysql versions I'm using, although I haven't 100% confirmed this. I have not installed any new modules or made any other changes. The last time is was accessible, my friend just added a blog post, like he's been doing for years.