The Select subkey under HKEY_LOCAL_MACHINE\SYSTEM maintains information about the control sets for the currently selected computer. The Select subkey contains the following named values:
Current REG_DWORD 0xN, where N identifies a control set
Identifies the control set from which the CurrentControlSet subkey is derived. If this value is 0x1, for example, the subkey producing the CurrentControlSet is ControlSet001.
Default REG_DWORD 0xN, where N identifies a control set
Identifies the default control set. If this value is 0x1, for example, the default control set is ControlSet001.
Failed REG_DWORD 0xN, where N identifies a control set
Identifies the control set number of the control set that was last rejected and replaced with a LastKnownGood control set.
LastKnownGood REG_DWORD 0xN, where N identifies a control set
Identifies the last control set that successfully started the system. If this value is 0x1, for example, the last control set known to be good is ControlSet001.