Comment 73 for bug 776999

I'm also affected. I thought things were going well with my W520: I got 12.04 64-bit working in discrete mode with Unity3D and it was all good until I installed VirtualBox and realized that VT-X was turned off in my BIOS. I turned it on and then could no longer boot (I need fast virtual machines so disabling VT-X isn't an option for me).

My current symptom is that it will boot with a lot of long pauses, show the purple blank screen, sometimes show the 'Ubuntu' screen with four progress dots, and eventually hang on a BusyBox screen after saying "(initramfs)".

I think I need to go down to 32-bit.