MSSQLServer Failure Audit Event ID 18456, Category (4)

We're running Windows Server 2003 x64, SQL 2005 x64, and MOSS SharePoint 2007 all on the same box.

We receive this error message in the event log every minute.  The strange thing is the user is NT Authority\Syste.

I'll post the text here as well as a screen shot.  Any ideas?  I've tried solutions recommended on eventid.net to no avail.

Source: MSSQLSERVER
Type: Failure Audit
Event ID: 18456
Category (4)
User: NT AUTHORITY\SYSTEM
Computer: PLATO
Description: Login failed for user 'NT AUTHORITY\SYSTEM'. [CLIENT: ]

Data: 0000: 18 48 00 00 0e 00 00 00   .H......
0008: 06 00 00 00 50 00 4c 00   ....P.L.
0010: 41 00 54 00 4f 00 00 00   A.T.O...
0018: 07 00 00 00 6d 00 61 00   ....m.a.
0020: 73 00 74 00 65 00 72 00   s.t.e.r.
0028: 00 00                     ..      

Hi

 For the error in the ERRORLOG, the STATE tell that the process doesn't have permission of the login database. It apears to use NT authentication, running as localsystem. The possible cause might be because your sharepoint services are also set to run with nt authority\system.

Modify the sharepoint services logon a/c credentials by opening the services mmc (start>>run>>services.msc)

the errors should go away. additionally check the version of SQL and upgrade it to SP2

bhanu