Comment 15 for bug 1167114

Also just experienced this on a desktop.

Just installed a bunch of updates, one of which was:
linux-headers-generic:amd64 (3.5.0.26.32, 3.5.0.27.43)

Since the system boots fine into 3.5.0.26, it stands to reason it must be this.
In a duplicate bug report, lots of people reported they have this issue on machines with older Radeon graphics cards,
specifically:

Radeon HD 3000 Series
Radeon HD 4000 Series

From reading the comments here, it seems like the bug also affects systems with other hardware.

Mine falls into the latter category. Off course, I'm running the noveau driver on that, since these HD cards don't support the newer xorg server versions, while noveau's good enough for my purposes not to downgrade.

Could somebody with this problem try to boot into 3.5.0.27 in recovery mode, I know it gets halfway there -- perhaps someone could pull up a root console after issuing a Ctrl-Alt-Del signal when it decides to stop booting? (I apologize, I'm in a bit of a time bind right now.)

I think it would be helpful to see what the "dmesg" command would say about the boot messages, if indeed it would work.