Outlook Crash on Open

In the last week, two clients on independent boxes have had the same problem, when opening Outlook (Office XP Pro), outlook generates an error and closes, will not open in Safe Mode.
<--- AppName: outlook.exe AppVer: 10.0.4510.0 ModName: outllib.dll ModVer: 10.0.4712.0 Offset: 0002d431 --->
Event Viewer shows Event ID: 1000, which when I go to Microsoft, shows “no information available”. I am able to open the pst file over the network on another box so it’s not corrupt, I have deleted and re-created the user profile on the box, have have unintalled and re-installed the MS Office XP – any suggestions?