ubuntu wont load up, just goes to (im not computer literate but) dos like screen

[crewrecline]

Again i will state that im not computer literate.  I had ubuntu 12.4 on an acer aspire.  i did an update and after it restarted ubuntu wouldnt boot up any longer and all im getting is a dos like screen.  again sorry if im saying this stuff wrong.  as soon as it boots up i get the ubuntu purple screen but then it goes to a black screen that says:
"stopping system v runlevel compatibility"                     [ok]
"starting"                                                                       [ok]
"stopping cold plug devices"                                          [ok]
                                                                                       [ok] stopping log initial device creation
                                                                                       [ok] starting save udev log and update rules
                                                                                       [ok] stopping save udev log and update rules

if someone can help me recover my ubuntu i would really appreciate it.