Office XP Calendar

We are currently experiencing an issue that seems to be intermittent.

SOME of our users experience a time difference when sending/receiving a calendar event to/from other users. We have found that on the receiving end, the Daylight Savings check box would not be checked but sometimes it is. We cannot pin point the root cause for this difference and obviously do not have the resources to check each individual users’ settings.

Here are the specs:

Windows 2000 SP4 and XP SP1 Mix
Office XP STD SP3 (Upgraded from Offive 2000 Prm)
Exchange 2003 in a native 2003 Domain
Users have Power user rights to local machine

My objective is to find an alternative to checking every users’ settings and at the same time, find out what caused this time difference. Any help would be much appreciated!