ISAPI Filter error

I hope this is the correct forum.

OK - All of the web services on my intranet box were shut down at 3 this morning. I see, below, in my IIS box system log.

Event Type: Information
Event Source: IISCTLS
Event Category: None
Event ID: 2
Date: 10/4/2005
Time: 3:46:47 AM
User: N/A
Computer: INTRANET
Description:
IIS stop command received from user NT AUTHORITY\SYSTEM. The logged data is the status code.
For additional information specific to this message please visit the Microsoft Online Support site located at: http://www.microsoft.com/contentredirect.asp.
Data:
0000: 00 00 00 00 ....

So here is the FIX

http://support.microsoft.com/default...b;en-us;899472

Now my question. I do not have any ISAPI filters installed. What else could be causing the error. This is the first time I have ever seen this error. Has anyone ever dealt with something like this. I've been searching MS TechNet, Google and AO but I'm not finding anything other than ISAPI errors and fixes.

Specs:

W2K Server - Patched
IIS 6 (Locked down using MS tool)
I have some OLAP Cubes running on the box, (Written prior to dot net)

Security and application logs show nothing out of the ordinary - less the above error and the service failures related to that error.

No strange activity on the network over last 24 hours.