Event ID : 1000

Issue : Outlook will not open because system attendant service is down.

Event Source: Microsoft Exchange Server

Cause : When you restart a computer that is running Microsoft Exchange Server 2003, the Microsoft Exchange Information Store service stops unexpectedly for several minutes.Outlook will not open because system attendant service is down.

Description : Faulting application store.exe, version xxxx, stamp xxxx, faulting module xxxx, version xxxx .
This problem occurs because the Microsoft Exchange Information Store service incorrectly calculates the offset value at the end of the header (EOH) for corrupted messages. This behavior causes an access violation.

Action Required :

1. Apply Microsoft Exchange Server 2003 Service Pack 1.
2. Apply IIS Stack Overflow Vulnerability Patch
3. Shut down Exchange and IIS. Rename the "...\mailroot\vsi 1" directory, create a new one and restart the services. This will eliminate any spam, or corrupt messages from the queues.

Ref.Link :
http://support.microsoft.com/kb/935468