Well I’ve heard back from my host and it is not good news. I do not know enough about the inner workings to know if their suggestion will make a difference. It seems odd that the blog would continue to work, as it does now, if the database was corrupt. Here is what they say:
Ultimately the problem is that specific pages (New Post, Edit Post, Customize Theme, et al) are not being rendered in their entirety. That is, a large portion of code is missing from the bottom of each of those pages. This code includes numerous JavaScript files that provide much of the functionality in the administrative control panel such as the Visual Editor. Because these scripts are missing, many of the features are broken. This normally signifies that there is a coding issue within your themes or plugins or your WordPress installation is corrupt (whether that be files or the database).
Unfortunately, after many hours of research and debugging, I have been unable to successfully correct the problem. I suspect however that the database is at fault as everything else has been ruled out. I’ve noticed that the table in your WordPress database that stores customizations and settings contains over 1,062,931 records. Most of these records pertain to themes, plugins, and other customizations (many of which are obsolete and not in use). Not only does this cause tremendous performance issues, but can cause conflicts that could possibly result in the issue you are seeing now.
My recommendation would be to export all of your content (pages, posts, tags, categories, uploads, and other media) and start with a fresh install (this means discarding your current database entirely). You can then import your content (using the exported XML file that WordPress creates) and make only the necessary customizations you need for your site, therefore correcting whatever database issue(s) may exist.
I am reluctant to go to all the trouble without being more confident that this will correct the issue.
What do you think?
Jackie