I have NVIDIA GT 540M CUDA 1 GB
Try this installation method:
1. Open terminal
2. Type prepare-kernel-source
3. Type cd /usr/src/linux
4. Type cp -rf include/generated/* include/linux/
5. Download the driver here
http://www.nvidia.com/object/unix.html
6. Type chmod +x /[path of your driver restored]/[nvidia driver name]
Disable nouveau kernel
1. Open Terminal
2. Type gedit /boot/grub/grub.cfg
3. Search for vga=791 and insert this script "nouveau.modeset=0" (without quote)
4. Reboot
After boot, and enter username and password, DON'T TYPE STARTX! Follow this instruction.
1. Type cd /[path of your driver restored]
2. Type ./[your driver installer].run--kernel-spurce-path='/usr/src/linux'
3. Installation has begin.

4. After intall your driver, don't forget to update grub.cfg by typing update-grub
5. Reboot your Lap/PC
Done
It's work for me. So you can see more effect on your backtrack screen.
Cheers!!! \m/