van will not start without a jump yet will try to start after trying and key removed

I went to start van and it would not start. it had lights on and buzzed and lost time on clock and radio stations. the first time I got a jump without the other car even being on. drove ten miles, parked and turned off and tried to restart it. It started. drove 1 minute to store, came out at wouldn't start with lights flashing and noises. got a jump and went home. didn't start after that. left it overnight and no start in the morning. got another jump and drove it an hour. left it overnight and no start. the lights and clock and radio blinking, it tries to start yet nothing.
I do have an aftermarket remote lock.
any and all help will be appreciated.