Support for Windows Vista without any service packs installed ended on April 13, 2010. To continue receiving security updates for Windows, make sure you're running Windows Vista with Service Pack 2 (SP2). For more information, refer to this Microsoft web page: Support is ending for some versions of Windows
If a domain controller is unavailable and a user's logon information is cached, the user will be prompted with a dialog that says:
Through the registry and a resource kit utility (Regkey.exe), you can change the number of previous logon attempts that a server will cache. The valid range of values for this parameter is 0 to 50. A value of 0 turns off logon caching and any value above 50 will only cache 50 logon attempts. By default, all versions of Windows remember 10 cached logons except Windows Server 2008.
For more information the default number of cached logons in Windows Server 2008, click the following article number to view the article in the Microsoft Knowledge Base:
Cached logon information is controlled by the following key:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\Current Version\Winlogon\
Data Type: REG_SZ
Values: 0 - 50
Any changes you make to this key require that you restart the computer for the changes to take effect.