2001 Saturn SW2 wont start

when I turn the key I lose all electrical power and car wont start. Gauges are stuck in position they were in the last time the car was running(fuel,rpm,temp) The clock is on when I get in until I turn the key or try to turn on lights, dome, unlock/window switches etc. After a few seconds clock will come back on without losing the time but dims in and out. Sometimes the security light is blinking but not all the time. this also goes out when everything else does. This happened once before 2 months ago but the next day it started after I went through the security code process. No luck this time. Any clues???