sometimes symantec v9 (or 10?) reports an error about windows update exe file
the problem is the login error insufficient resource to logon, default user profile will load
scan for virus / spyware , no luck
scan disk, no luck.
its a HP desktop with 2*256 MB ram
eventually swap the memory moduels to another bank,
then the logon profile failure to load problem vanished.
when this problem happens, the safe mode is ok to load.
its a hardware mainboard / memory problem, I will find out next week to see if that client comes back to me with the same dreaded problem