Text in Long Document Hidden

I've run into a problem while working with a long document (650 pages),
using Word 2002 running under Vista Home Premium. I've previously worked
with much longer documents on the same system without experiencing this
problem.

The problem is this. With the Normal View in use, I copied some text (about
two pages) from elsewhere in the document to the clipboard, then pasted from
the clipboard into page 162. Only about half of the copied text appeared on
the screen. I switched to the Print Layout View and found that all the
copied text was correctly displayed.

In Print Layout View, I noted the page numbers of the text that was
correctly displayed in Normal View, and the text that was not displayed in
Normal view.

On switchig back to Normal View, I noticed that the status bar showed the
last correctly displayed line positioned on page162 at 7.4". In that view,
the next displayed line was shown positioned on page 164 at 22". Nothing in
between was displayed.

For some reason that I don't understand, Normal View seems to have lost
track of part of the document, while Print Layout View does keep track of
it.

In PrintLayout View, I used Find to locate some text that is within the
region that Normal View does not display. Find could not find that text.

I tried saving the document with a new file name and then looked at the new
file, hoping that Word might have some way of correcting the problem. No
such luck. The new file shows the same behavior.

Can anyone suggest a solution to this problem? I'll greatly appreciate any
suggestions.

Gordon