The problem of not working

My car is 2002 model 1.4 8v gasoline 206.

There is a problem that happened to me 2 times.

When I get into the car, when turning the ignition, no lights are on and the car does not work. But the battery works when I remove the polarity head and put it back on. My clock and tape settings are reset. I've had this problem 2 times in the last 2 days. Problem. What do you think?