After running OE6 for a few hours and switching to sent items, out-box or
deleted items, then back to my inbox, it has emptied itself. Refreshing
does not cause the entries to return. If I re-boot Windows, the items in
the in- box have returned and it works normally for a few hours, then
empties again and I have to re-boot again.

Any ideas?

Win 98se, 300 MHz P11, 320megs Ram. IE6, OE6, CA anti-virus, ZA free,
several anti-spyware preventers, Comcast broadband cable.