I have just updated my 12.10 to 13.04. Everything is updated. But I can only boot to a black screen. I mean after the GRUB interface and purple screen. And I can hear the voice of the password interface. But it is only the black screen. It all works OK in 12.10. But it can work in the recovery mode. I mean go into the recovery mode and choose resume. And then everything is OK. But when loading kernel, the screen is dirty. I don't know why and I have Googled a lot. But no resolutions works. My graphics card is Intel GMA HD 4000, tested as VESA: Intel® Sandybridge/Ivybridge Graphics. I have been trapped in this for a whole day. I do need help. Hope someone can help me. By the way, the kernel is 3.8.0-19 if it helps.