Pressing the power button on my x120e kills the power instantly and hard resets it.
It doesn't always do this, maybe 1 out of 4 times, but the longer the computer is on the more likely I feel it will happen. Pressing the power button also kills the power instantly in the bios 100% of the time and when windows is booting.
I'm not sure if that's normal or not.
The default setting for the power button is to shut the machine off. If you press and hold the button, the machine will turn off. If you just press and release the button, depending on power manager settings in Windows, the system will suspend, hibernate, or shut down in an orderly fashion.
In BIOS, the power button will shut down the system since Windows and power management functionality has not been loaded. Under Windows, the power button function can be changed.
Open the Control Panel
Select Power Options
On the left click, "Choose what the power buttons do".