Err:7 xenial-backports InRelease. I used this method to install Notepad in my ubuntu since it become difficult to write for my.
Burn it to a DVD or create a bootable USB stick using LiveUSB Creator called. After you have created the installer bootable media, place your DVD/USB into your system appropriate drive, start the computer, select your bootable unit and the first CentOS 7 prompt should appear. At the prompt choose Install CentOS 7 and press [ Enter] key. Auto Detect Installation Type 8.