How can I reboot my MacBook Pro after USB hard drive made it hang?

Question

I plugged in a 1 TB Hitachi USB drive to my MacBook Pro, the rainbow circle icon in Finder spun for about 1 minute, then the whole operating system froze, even closing the lid doesn't make it go to sleep.

How can I reboot my MacBook Pro?

• There's no Delete key for a CTRL-ALT-Delete.
• I can't find a reset button on it.
• I can't seem to turn it off and it has at least 6 hours of batteries left.
• Command + Option + Escape didn't work.

Answer 1

Press and hold the power button for about five seconds. (This works on Mac and PC, in my experience.)

Your MacBook Pro should power off. (Unplug the hard drive and boot up again.)