I was instructed to start my computer holding down t, I am unable to log into my computer if it boots regularly. This start up mode allows me to use another mac, connect them using a fire wire cable and an external HD. I was just opening the finder and literally copying the entire HD using ctrl c and ctrl v to my external HD, this is when I got the message saying that I will need permission to access the system preferences. I will try the link that was attached, Thank you for your time.