Restart Ubuntu Linux safely when it is frozen or locked up!

If anyone faces a freeze with Ubuntu where you cannot do anything, then this will certainly be helpful if you want to reboot the OS as cleanly as possible without damaging their HDD's or losing their data.

In case of a freeze where you cannot do anything, simply press Alt+PrintScreen+R+E+I+S+U+B, keep in mind that the underlined keys must be kept pressed through the rest of the sequence AND that you will need to keep holding the sequence keys for a small period of time before going to the next one so that their actions can be carried out properly (For example, hold the R key for about 1-2 seconds before moving on to S). If the sequence does not work at first, then increase the time period between each sequence key press and try again.