Safely Reboot Totally Frozen Linux Box

When Ur Linux OS freezes completely,press and hold Alt + print screen keys and simultaneously type REISUB

THIS WILL REBOOT UR LINUX SAFELY,
HERE WE ARE PASSING PARAMETERS DIRECTLY TO KERNEL

• R: Switch the keyboard from raw mode to XLATE mode
• E: Send the SIGTERM signal to all processes except init
• I: Send the SIGKILL signal to all processes except init
• S: Sync all mounted filesystems
• U: Remount all mounted filesystems in read-only mode
• B: Immediately reboot the system, without unmounting partitions or syncing

This Method Should be attempted only if Alt+backspace fails