Disappearing emails in Outlook Express

I have Windows Home XP, and have downloaded SP2.

Since downloading SP2 (may be unrelated), have had the following problem: whenever I reply to or forward an email from my Inbox, the original email completely disappears from Outlook Express. It does not go to the Delete folder or any other folder that I can find (I do all permanent deletes from my Delete folder).

I have the following questions:

What causes this?
How do I fix it?
Can the "lost" emails be recovered?

Will appreciate all responses.

 

Found answer from another source, but thought I would post it here in case it might be helpful to someone else. Somehow an option in Outlook Express was changed.

To correct, in Outlook Express, click on "View" at upper left. On drop-down list, select "Current View", then select "Show all messages".