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:

Error: GNOME Power Manager have not been installed correctly_gnome error

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