Re: New Installation of 12.10 (Desktop 64) won't boot
Good instructions for booting nomodeset are at http://ubuntuforums.org/showthread.php?t=1613132. Scroll down to the heading "How to temporarily set kernel boot options on an installed OS (not wubi)". (I assume from the fact you installed from a USB that you didn't install from within Windows...)
With any luck, that will allow your system to come up once. Then, you can open Additional Drivers or Hardware Drivers (depending on your release) and install the drivers for your GPU.
Jane, stop this crazy thing!