I think your problem here is simple. (I could be wrong, if I am someone correct me.)
Your inittab file (located in /etc) has a line that reads like this...
# Default runlevel. (Do not set to 0 or 6)
If your's looks like that, ie: with a 3, then the system will boot, leaving you with command line.
You could log in from there, and then run the command "startx" and you should be good to
Or, you could alter your inittab file, change the 3 to a 4 and then it should boot up normally, with a graphical login.