The HP Probook 4540s has two recalls that pertain to both its AC Power Cord and battery. (1) To check and see if your AC Power Cord is affected by the recall, please visit, https://h30652.www3.hp.com/ (2) To check and see if your battery is affected by the recall, please visit, https://h30686.www3.hp.com/
To set up the fingerprint scanner you must install HP Protect Tools. After installing the wizard, follow the prompts, which will instruct you to register your fingerprint. After the setup is complete, you’ll be able to use your fingerprint to log in!
(1) Is the power adapter cable plugged into the laptop? If so, make sure the adapter is plugged into an outlet and that outlet has power. (1.1) If this solves your problem, your battery may either be faulty or not charged. Try letting your battery recharge for a few hours then power down the machine. Unplug the laptop from the power adapter and turn on the machine. If it doesn’t turn on, then your battery will need to be replaced. (1.2) If this doesn’t solve your problem then you may have a faulty power adapter. While plugged into an outlet, is there a light on the adapter? (1.2.1) If there is, the cord to the adapter may be faulty and needs to be replaced. (188.8.131.52) If not, then the adapter may be faulty and needs to be replaced. For more information check the device Troubleshooting Page