What to do to when Ubuntu is slow in booting up:
1. edit the /etc/usplash.conf to use xres=1024 yres=768, then
2. sudo update-usplash-theme usplash-theme-ubuntu
If you are unable to get XOrg working, use Ctrl+Alt+F1 to get into tty1, login and follow steps 1 and 2.
[Thanks to the Ubuntu Forums]