Hi all.
I'm failing to boot Ubuntu 12.04 (Live CD desktop amd64 edition)-

After choosing Try Ubuntu from the menu, I get stuck in a black screen with a Flashing Prompt for more than 15 minutes, that does not repsond to any keystroke.
I guess the problem has something to do with Graphics Drivers, but I can't really be sure.

I am using an nVidia GeForce GTX550Ti Graphics Card.

Any help?
Thanks in advance!