try opening it up and seeing if the battery is unplugged. when i upgraded my lenovo's hdd to an ssd i had to unplug the battery, and i forgot to plug it in again when i turned it on. i turned it on and unplugged it a couple times, then clicked the battery icon on my taskbar and it said "no battery present"
so i had to unscrew ALL the screws again and i plugged it back in, then it worked again. either your battery is unplugged or is completely kaput