How are you editing the menu.lst?
for me I would use terminal command
Code: Select all
gksu gedit /boot/grub/menu.lst
At blinking cursor can you get to console by entering Ctrl+Alt+F1 or maybe try Ctrl+Alt+F7? And if you can get to console and enter login name and password, does x session start by typing in " startx". When did the blinking cursor occur?