InDesign ME version has lost my grids, guides, frames

[RonLF06]

I'm near finishing my 4th English/Arabic book design with InDesign CS4 Middle East version, and suddenly it's is refusing to show grids, text and picture box frames, and guides.
Keyboard shortcuts don't work (Command and nor does the Menu (View>Grids & Guides>Show guides).
I've restarted the computer (G5 desktop, OS 10.5.8) and uninstalled and reinstalled from disk. No change. Is there something I've missed in Preferences?
Can anyone help? The publishing deadline approaches fast!

PS I'm posting this as a new thread because I didn't put a useful heading up.

 

[RonLF06]

Just discovered the problem is specific to the book file. The cover is a separate file, and grids, guides and frames all turn on and off as normal. So it's not the application.
Somewhere, something's changed – presumably in Preferences – on the book file.
But I can't find what.