Hmmm there are a lot reasons it might not work. Often, it's because of a quite complex reason.
What you can try:
- Press the 'off' button on the laptop. Maybe it only works after pressing Ctrl+alt+F2.
- Press Ctrl+Alt+F2 and then Ctrl+Alt+Del (this will reboot, but you can press the 'off' button while in the bios/boot screen, when it displays the Thinkpad logo). Sometimes, I have to do this more than once before rebooting actually happens.
- If all else fails, you can press the 'off' button for ~5 seconds until the system goes down. This is basically the same as switching off the power, so not recommended, but sometimes it's the only thing that's left.
Note, Ctrl+Alt+Fx switches virtual terminals. You can go back to the graphical screen with Ctrl+Alt+F7.
This is probably too late, but I thought in case it happens again.