First and foremost, disconnect from the internet, not only is it the responsible thing to do to protect others from your misfortune, but it also prevents the infection from phoning home. Then i will try to utilize what i already have on the system to eradicate the infection, if this fails, i will then pull out my toolkit "flash drive" and attempt to do so either directly, or via safe mode. After removing the infection, if the damage to the system is minimal, i will repair the files and move on with my day, if it is extensive damage done to the file system, i will then reformat instead of wasting time trying to repair it. I keep all of my personal files backed up constantly on external devices and not directly on the system ,so there is no need to worry of it being taken, nor any worry of having to reformat if needed.