I have a laptop with an nVidia Geforce 7150 (630 chipset) and I can’t boot the live CD to install. I tried booting into VESA mode as well, but all I get is garbaged graphics either way.
Try entering the boot code in the initial grub boot screen menu:
nomodeset
…
that should force the boot of the graphics portion to change from the ‘nouveau’ driver to the ‘nv’ graphic driver.
More help here: