There is only one file type that uses the .LOGONVISTA extension:
LogonStudio Windows Vista Logon Screen
Custom logon screen that can be loaded by LogonStudio, a program for customizing the Windows logon screen; may be used to change the way the Windows Vista logon screen looks.
NOTE: LogonStudio logon screens for Windows XP use the .LOGONXP extension.
Updated: July 5, 2009