delayed outlook

I have 2 seperate clients that are both running Winxp Pro with office 2000 when there new mail hits the exchange server it is not sent to there outlook until they click on another feild IE tasks,sent,outbox. If they stay in there inbox with focus on that the new mail does not arrive. Both users are on domains with no other workstations having the issue. I set one of the two up on a new system and still had the delayed retreival sounds like a profile error anyone else have this problem or how to fix