Home page will not display the correct existing or new content

I have a problem that’s really stumping me and I’d be grateful for any assistance. A little while ago, I installed a plug-in that took my WP over the 32B memory limit that my hosts allocate. Result: Stuff stops working. I asked them to increase the limit to 64 MB, which they did, and my site reappeared.

However, on the home page only (a static page), I have a really puzzling error. The home page does display, but it is displaying just one post (the last post) when it should be displaying this post and quite a lot of other stuff besides. I’m using the Word Press Access Control plug-in, so that logged-in visitors should see different content to random visitors (Which, until the memory business described above, worked fine). But, whether logged-in or not, all anyone sees now is just this one post. Editing the home page works (that is to say, changes are stored, saved and display OK in the editing screen), but are not reflected in the displayed page.

I’ve tried disabling the plug-in that over-burdened the memory.

I’ve tried disabling all plug-ins (and then enabling them one by one)

I’ve even tried setting a completely different static home page in the admin UI (Settings > Reading) and in my theme customisation (I’m using twenty-ten).

I’ve tried switching to a different theme.

And even more weird, I’ve actually deleted the home page (moved it to the ‘Trash’ folder) and still I just get to see this same old post. Header and footer are fine, widgets are working – not that I have many, just a log-in box.

I hope I’ve described this problem well enough to indicate what’s happening. I am at a loss what to try next – so if anyone has any ideas, I’d be pathetically grateful.