10.4.2. Booting into a Graphical Environment

If you have installed the X Window System but are not seeing a graphical desktop environment once you log into your system, you can start the X Window System graphical interface using the command startx.
Once you enter this command and press Enter, the graphical desktop environment is displayed.
Note, however, that this is just a one-time fix and does not change the log in process for future log ins.
To set up your system so that you can log in at a graphical login screen, you must edit one file, /etc/inittab, by changing just one number in the runlevel section. When you are finished, reboot the computer. The next time you log in, you are presented with a graphical login prompt.
Open a shell prompt. If you are in your user account, become root by typing the su command.
Now, type the following to edit the file with gedit. 
gedit /etc/inittab
The file /etc/inittab opens. Within the first screen, a section of the file which looks like the following appears: 
# Default runlevel. The runlevels used are: 
#   0 - halt (Do NOT set initdefault to this) 
#   1 - Single user mode 
#   2 - Multiuser, without NFS (The same as 3, if you do not have networking) 
#   3 - Full multiuser mode 
#   4 - unused 
#   5 - X11 
#   6 - reboot (Do NOT set initdefault to this) 
#
id:3:initdefault:
To change from a console to a graphical login, you should change the number in the line id:3:initdefault: from a 3 to a 5.

Warning

Change only the number of the default runlevel from 3 to 5.
Your changed line should look like the following: 
id:5:initdefault:
When you are satisfied with your change, save and exit the file using the Ctrl+Q keys. A window appears and asks if you would like to save the changes. Click Save.
The next time you log in after rebooting your system, you are presented with a graphical login prompt.