We're trying to roll out this new NW client but have reports of many blue

The first blue screen is usually at login time (mentions winlogon.exe) -
this seems to have been fixed by logging in via safe mode and deleting reg
[-HKEY_LOCAL_MACHINE\SOFTWARE\Novell\Graphical Login\NWLGE\NetIdentity

However, some users are still complaining that the machine now reboots in
the middle of the day (not just at login).
We are also rolling out Zen7 agent and Symantec Antivirus v10. (Crazy?? No,
we're trying to go one step at a time).

We are using contextless ldap lookup - but the reboots happen sometimes 3 or
4 times a day.

A lot of machines work fine, but a variety are not ok.

Any suggestions?