Are you running a proprietary video driver? It might be worthwhile to disable it in case it became incompatible perhaps after a kernel upgrade.
Did you perform a graphical login prior?
First, you might try booting an older kernel to see if that runs for you. Your bootloader such as grub might help you pick an old one.
The older kernels are actually combinations of kernel + initial ramdisk that contains the version of your graphics drivers that were being used at that time. It could be a way to test the hypothesis.