MacBook Pro 2021 is starting up on a blank black screen

P_baa wrote:

One day when I opened my MacBook Pro 2021, it started up on a blank, black screen. All I can see is the mouse. I have no power button to press and hold in order to restart it. What can I do?

If your Mac starts up to a blank screen (white, black, gray, or blue)

https://support.apple.com/en-us/HT210905

You can always force a shut down in order to reboot— hold the power button/TouchID for ~6-10 sec

ref: Log out, sleep, wake, restart, or shut down your Mac - Apple ...