What is the exact model of the laptop and if it is still under warranty I would suggest calling Dell tech support. With that being said have you tried a hard shutdown by pressing the power button for at least 4 seconds? If that does not help try a reset. Disconnect the battery and unplug the adapter. Then press and hold down the power button for 30 seconds. Then reconnect everything and try to boot again.
Hi My laptop has froze/does not respond  and now I can not even shut down. It is 11 months old
Laptop will not respond