Fix a Frozen System with the Magic SysRq Keys

Fix a Frozen System with the Magic SysRq Keys
"You finally got your Linux environment to crash. Ctrl+Alt+Backspace does nothing, nor do the F-keys. You know you shouldn’t have installed that bad driver, but you did it anyway. So you reach for the power button. Stop. Mashing in the power button to reboot could cause a problem if your hard drive is still being written to, and usually causes more problems than it solves. The Linux kernel includes a secret method of restarting your PC should it ever stop doing it’s job."