How do I diagnose why numerous xp (and possibly Win7) boxes arebeeping from winlogon every 10 seconds?

I work in a building with a couple hundred other people, all using either WinXP or Win7. About a week ago I noticed that my computer was "beeping" about every 10-60 seconds. It's actually the "trumpet" sound that you get from "Windows XP Critical Stop.wav". I used SysInternals ProcessMonitor to watch for accesses to that file, and I found it was being done in "WinLogon"..

I was about to send a note to our building administrative assistant when I saw a note she sent to everyone in the building asking if anyone else was seeing (hearing) the same symptom I was about to tell her about. Apparentlymany people have been getting this, and it's been going like this for a week now.

I've looked in the event log, and I don't see anything significant, or associated with these sounds.

What else could I do to try to diagnose why this is happening? It's obviously a result of something that our corporate IT installed, but I don't holdany hope of trying to contact someone who might know about what they mighthave installed. I'd like to at least see what I can figure out on my own.The admin. asst. filed an IT support ticket, but that was a week ago (we're part of a very large company).