Right. I have now created a completely new form, based on the qryBook with a combobox based on the tbl.book.
The combobox initially put the bookid in the query, (it was bound to column one - the rowsource is
SELECT tblBook.BookID, tblBook.Book, tblBook.Price, tblBook.Frequency
FROM tblBook
ORDER BY tblBook.Book

. When I changed the Bound Column to 2, it then entered the name of the book.
Then I added the code me.Price=me.Combobox24.column(3) to the AfterUpdate event (I put column 3 because of the earlier problem mentioned above - I thought if the book title was column 2, then the price should be column3)
Then tried to run it and I again got the "Module not found" error message. Trying to clear this then brought up the error about the Data Entry form being misspelt. This took several clicks on the OK button to clear and it then closed the database completely.
I think I will attach the database so that you can perhaps spot what I am missing.
The original form is frmData, the new form is frmEnterInfo - I have not done any rearrangements, or layout on this yet.
I hope this works OK.
Many thanks for any help you can give me, I am getting even more grey hairs than I had at the beginning of the week.