Compaq m2105us laptop

Question

i was typing a email and laptop turned off ..no power ..pluged it up without battery and booted up fine then shut down..again now wont power on at all ...the laptop is fairly new has been takin care of ..but theres no power no where.with or without battery..the ac plug is pretty tight so i don't think it is the ac plug on laptop. what would make it do that ? would appreciate some help thanks .........mike