code blinking

That's the theft light. Your key either isn't programmed or isn't being recognized by the vehicle for some reason. Has anything changed since you last used the car, I.E. new radio or key?

i think my husband put a radio it after the last time he drove it an a new battery i dont know what I.E means

If he tied the radio into the wrong wire somewhere especially for the key on for the radio that may be the issue. Whatever that has changed since the last time it ran in the absence of any other cause is where he needs to start.