Thanks for reply Soybean.
I have today checked Adobe Reader and find that the document has now gone.
To check again, I duplicated the procedure - loaded the disk, clicked the manual to bring it up in Adobe, exited and removed the cd - and after this the document is still listed in the Adobe file menu, even after closing and reopening the program. It seems to be deleted only when the pc is shut down. This is what I didn't do first time. Anyway, all clear now - thanks again.