win2000 unable to shutdown normal way

hi, i’ve had win 2000 pro,service pack 2 installed and operating fine for about 10 months. the problem is now when i go to shutdown the machine [start,shutdown,hit enter]it doesn’t shut dow, doesn’t even lose it’s resolution like it used to before shutting down.now i have to manually turn off the power to it,but when i turn it back on, it doesn’t go thru scandisk.also, it won’t restart either.jim.