The most likely thing is - it's failed.
You can check all the internal cables are fully seated, and try Removing it in device manager and letting it be re-detected - but after all that, they're probably the most unreliable unit inside the system.
Fujitsu Lifebook P727 laptop review
Microsoft Paint set to die after 32 years
Mac power user tips and hidden tricks
Comment désactiver la saisie intuitive et paramétrer votre clavier ?