User password change, reboot. Password change is not valid after reboot.

Hi,
I am doing the following from a DCOM server program on Windows NT 4.0 server.
Changing the password for a user using NetUserSetInfo(). After setting the password cross verifying the change with LogOnUser() function with new password, which is successful. Immediately shutting down the machine with IntiateSystemShutdown() function with parameters
timeout - 0 sec
bForceApplsClosed - TRUE
bRebootAfterShutdow - TRUE.

After the reboot, sometimes the user password is not the one, instead the old password before change. Am I missing somthing here? Is NetUserSetInfo() is supposed to save the password for user?
Do I need to flush the registry for this operation, if yes, which key in registry should I flush to save the password to disk.

any thoughts? Thanks in advance.
Kumar Talinki.
[854 byte] By [ktalinki] at [2007-11-17 19:55:56]