typedef enum _KTHREAD_STATE
{
         Initialized = 0,
         Ready = 1,
         Running = 2,
         Standby = 3,
         Terminated = 4,
         Waiting = 5,
         Transition = 6,
         DeferredReady = 7,
         GateWait = 8
} KTHREAD_STATE;

Windows Vista Kernel Structures