Ultra VNC ctrl Alt DEL not working

Ultra VNC ctrl Alt DEL not working?
win7

C:\> reg add HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /v SoftwareSASGeneration /t REG_DWORD /d 1 /f

source:
http://forum.ultravnc.info/viewtopic.php?t=16986
https://forum.ultravnc.net/viewtopic.php?f=9&t=27079