then either your adapter is dead or the power jack is broken inside the laptop because it should be powering your laptop at least if the adapter was working and you wouldn't have 5 mins left. you would have power, and that case, it would be the battery or the charging circuit, but if you get no power, adapter or adapter jack.
Try wiggling the jack and see if it powers up, or if you have a multimeter, test the adapter for power.