ETrust definition build 30.3.3054 nuking Windows Server 2003
ETrust is misdetecting lsass.exe as Win32/Lassrv.B, leaving servers unbootable.
Instructions on how to recover lsass.exe and get your server going again, and how to stop Etrust from immediately re-deleting lsass.exe can be found here:
I really do wonder, sometimes, how much testing happens before definition builds are released - "server down" is a seriously bad event.
Note: The SBS team have also posted about this problem on their official blog:
When you restart Windows Server 2003, the computer may display a gray screen or may appear to stop responding:
Edit 10 September - more important info: