Yes, this is exactly the point.
Not only did I reboot, but I also re-installed Office 2000 ! I cannot do more, but I know from experience on my own PC that re-installing Office 2000 is virtually useless.
When the "Last Seven Days" option is selected, all messages are visible in the reception box, whatever their age !
Of course, I tried changing options forth and back in every possible configuration. All ot them work, except the infamous last 7 days.
Anayway. thanks for caring about my friend's problem.