Diky moc,
skusim podla prispevku:
secpol.msc is just a fancy front-end to the registry.
The key in question is HKLM/System/CurrentControlSet/Control/LSA and the value is named LmCompatibilityLevel.
"send ntlmv2 response only" (vista default) = 3
"send ntlm response only" = 2