well here's my problem

my '97 venture will not crank it all started last night i got home from work everything was fine. i was going to go to the corner store later and it made a sound like the battery was dieing cranked over very sluggish and then nothing. i thought right away it was the battery so i switched out with my wifes car and nothing. everything lights up,but it won't crank over any ideas?
thanks,elizar22

Bad ignition switch or bad starter. Do you hear a clicking sound when you try to start it?