All posts have disappeared – 404 not found – but I can see them listed in admin

Today I went to edit a post and it was not updating. Afterwards I checked another post and got an error message, saying

You attempted to edit an item that doesn’t exist. Perhaps it was deleted?

UPDATE: I could see the posts listed in Posts but WordPress earlier, but now they are not showing. Although it does still say 221 posts published.

The homepage is blank.

The latest posts are listed on the sidebar widget, but clicking them leads to 404 page.

I have uninstalled all Plugins and reinstalled the latest version of WordPress. No plugins at all are currently active.

I tried using one of the default WordPress themes but no differnce. AS the error is in the admin / edit pages too I guess the problem is deeper than that?

I added a new post only a week ago, it was working OK then.

This is the website

I have also tried resetting the permalink settings.

Any advice on what to try next? I did a posts/pages export, so might have to try delete all and start again. But worried that the post information is not there…..

UPDATE. I looked in phpmyadmin at the posts table and it says

#145 – Table ‘./sharehol_wrdp1/wp_posts’ is marked as crashed and should be repaired

No idea how to repair ….