Hello Rob,
Would you please tell me how your macbook pro problem ended?
Since yesterday, it seems that I have the same problem that the one you described. (my mbp is also from 2006, with Ati Mobility Radeon X1600):
A column of broken horizontal lines to the right of the mouse pointer and no way to start it (“a pale blue screen with the mouse pointer and column of lines”)…. except with extensions unactivated.
A new installation of Os X from the installation disk didn’t change the problem.
Thank you to inform me how your problem ended, if there is still hope or something.
Thank you Rob,
Jonathan