[AlexBell]

Thanks for the suggestions, but none of them work.

Is 'the small x button at the end of the searchbar' the gear icon? I don't see any button that looks like an x. The button at the right end of the searchbar just gives me a list of books - or search headings I may have used.

If I hit enter with an empty searchbar the last ebook on the screen from the search is highlighted, but that's all. Pressing Esc does nothing.

I've installed the latest version of calibre, but still have no success.

PS Whereabouts on my Windows 10 hard drive are the ebooks stored? In simple words please; I'm not very good with computers. At least I could check whether the ebooks are still there.