TSGL: 2nd request -Outlook Express experienced

[EDLYNN]

I use XPPro SP2 and OE6 + Firefox.

1. Somehow OE removes a message from my Inbox subfolder, after ONE reading, and sends it somewhere - I believe to "store.dbx" - (After this first reading, I either delete it, or close it to return later for reply. But it disappears before I can return to it.)
2. Where is the corrective fix for that unwanted action?
3. I cannot open the .dbx folder which specifies OutlookExpress as the program which is associated with it. Trying to open them with another program like Word2000...either yields nothing, or unreadable unconverted text.
4. I suspect that this archiving OE action has even taken UNREAD messages and tucked them away in the storage files whose titles are the same as my active subfolders under my Inbox, ie. "sent items.dbx", "the-beach.dbx","tsgl.dbx"...

I did not make up any message rules like that, or remember checking off a box somewhere to authorize such action. I don't know for how long it has been going on - but at least 3 months.

I do not use McAfee, that at one time had caused a similar set of problems which they had 'fixed' with a patch. I use Panda Software's Titanium  Firewall and anti-virus, AdAware, Spybot, and Windows Defender.

Please help. I've got to get rid of this action, as it is destroying my emailing abilities to reply to read messages and respond to lost correspondence.

Thanks.  ED