At our school, the Novell Client for Windows v4.91 SP1 appears to be
causing errors, mainly 0xC000021A (STATUS_SYSTEM_PROCESS_TERMINATED), which
is WinLogin dying. The error is only caused after DfrgFat.exe error saying
that the memory could not be written. This only occurs after the machines
in question start defragmenting the HDD, 15 minutes after the login starts.
This is common to only one set of machines, which are cloned.

Any ideas?