I'm having trouble figuring out why backtrack isn't booting properly. (Gnome 64bit)

Firstly I would like to say that it works on my desktop perfectly fine but then when i try on my laptop it doesn't boot properly.

When I select normal/text mode it will start loading up everything then just before it goes to the startx screen, half the screen goes black and lines go through it.
But then when I run it in safe mode everything works perfectly fine...

Any ideas on what could be the problem.
Thanks Jem.