I have Ubuntu 12.10 installed on a Lenovo SL-510 laptop.
Previously I had a boot issue which resulted in a blank purple screen, that was solved using boot-repair to reinstall GRUB.
Right now it once again fails to boot. Selecting Ubuntu in the GRUB menu results in an empty screen with a command line cursor in the upper left corner.
Before this problem started, I got a scheduled updates notification, but it failed to install for some reason. This may or may not be relevant, but when the notification popped up, Transmission Bittorrent Client stopped downloading and wrote that the disk is write-protected.