Redirect to Install

I just searched the forums and it seems like this issue has come up a lot, but those threads are all closed with no answers in them. So here goes.

My blog (3+ years old, 200+ posts) suddenly redirects to the install page. I wrote a post this morning, normal procedure, looked at a few times after publishing. But I don’t go into the database or wordpress files at all, just work from the dashboard. So what happened and how can I fix it without losing my data.

On hold waiting for my server to help now, but not hopeful….
thanks!!