I just read the last post on this subject of "nssstub.exe" error message during log on
I also have the same problem as of yesterday after I installed 'divx player'. The Program was installed without any ability on my part to alter it's install. I am a tech and I always use custom installs and it was not available in this case. Anyway, it didn't actually install nssstub, it just install what it's called now - Install_NSS. It is in the Program Files\DivX folder as a subfolder called Symantec. It also puts an icon on the desktop called Install_NSS. It also has Install_NSS in the scheduled tasks folder and it also reappears after deleting everything upon restart. This scheduled task has been given advanced security permissions to run as the username as admin, administrator rights and also System rights with Full Control, with special access for auditing to everyone and to ANONYMOUS LOGON. The owner is set as Administrator(Computername\Administrators). It has no program in Control Panel\Add or Remove Programs (Probably because I didn't install it yet and it is not installed when DivX Player is installed). It also has NO files or folders in Program Files\Common Files. The name of the file in Program Files\DivX\Symantec is also different. It is now called "scstubinstaller.exe", and has along with it 2 more files - SYMCCHECKER.DLL and isconfig.dat. I read that you never found out how to get rid of it. I hope this helps. The program points to an .exe file in the users temp file (C:\Documents and Settings\users name\Local Settings\Temp) called "setup.exe". The file has 0 bytes but is reinstalled upon reboot. Upon checking it's properties you find it has zero bytes, it is a msdos file, it will run in conventional or MS-DOS protected-mode (DPMI) memory. It is set to 'Restore settings at startup' on the screen tab. And Security tab gives Full Control to Admininstrators, username administrators, NETWORK SERVICE, and
SYSTEM. It's Advanced special permissions are same as the scheduled task. It also has (on the Program tab, advanced button) Windows PIF Settings set up - Custom MS-DOS initialization files - %SystemRoot%\SYSTEM32\AUTOEXEC.NT and %SystemRoot%\SYSTEM32\CONFIG.NT. There are no msconfig settings and there is a registry setting in runonce - HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce
NSSInstallation REG_SZ C:\Program Files\DivX\Symantec\scstubinstaller.exe /runonce
I hope some of this helps anyone reading this for help in the future.