Ran into the problem as "GNOME Power Manager have not been installed correctly", and cannot get into the system, use ALT+CTR+F2 to login to the text command line, spared some space,  solved the problem. 

captured the problem screen shot as:

After entered the text command line, found the root directory disk space 100% used up, tried to make space for the disk. Used some commands as:

check the disk space usage:

df -h

clean the yum install cache:

yum clean all

check the space usage of each folder,

du -hx --max-depth=1 /

list out each file size:

du /var/cache/* | sort -n

find the files size more than 100M

find / -type f -size +100M