I can run it in safe mode and get the root prompt, but if I let it boot normally I just get a black screen. A similar question was asked here:
but I don't have a Nvidia graphics card. I am able to boot 3.2.0-43 just fine.
I did find this error in the kernel.log after trying to boot 3.2.0-51:
Aug 11 12:03:26 iceman kernel: [2.672181] [drm] MTRR allocation failed. Graphics performance may suffer.