I am hoping somebody out there can assist me; I notice from previous posts that most questions on this subject go unanswered.
I am using Outlook 2003 and have done so for many years; all of a sudden emails older than 7 days in my inbox disappear.
Auto archive is unchecked and no inbox folder is included in the archive folders.
This has created major problems for me; can any one assist?

I've seen this happen before, and it wasn't an auto-archive problem. Check your Views setting in Outlook. Click the Views > Current Views menu and see if it's set to Last Seven Days.

All the emails will still be there. They're just hidden by the view.

-SW

Spot On !!!
That was the problem; it never ceases to amaze me how a P C seems to have a mind of its own.
This alteration was made without any input on my part.
Thanks Heaps.