I have Kubuntu 12.04 installed on a Dell Studio 1537 laptop, which is prone to occasionally overheating and turning itself off. This has happened a few times before, but without consequence. Yesterday, this happened and I haven't been able to boot since. Some updates were being installed at the time of the crash.
The GRUB menu appears as normal, but none of the options (normal or recovery, or any of the kernels listed) will boot. The dots on the boot screen continue to move indefinitely (I've left it booting for over an hour) but the hard disk access light turns off after a short while and nothing else seems to happen. The system will then not respond to anything except turning the power off. I have a Windows dual boot which works normally, and a bootable Tinycore usb stick. I don't have a live CD, but I can make one if necessary. The following debugs are from attempting to boot in recovery mode (kernel 3.2.0-27-generic):-
Begin: Loading essential drivers ... done.
Begin: Running /scripts/init-premount ... done.
Begin: Mounting root file system ... Begin: Running /scripts/local-top ... done.
Begin: Running /scripts/local-premount ... done.
Begin: Running /scripts/local-bottom ... done.
Begin: Running /scripts/init-bottom ... done.
fsck from util-linux 2.20.1
udevd: unknown key 'BUS' in /etc/udev/rules.d/70-lego.rules:2
udevd: invalid rule '/etc/udev/rules.d/70-lego.rules:2'
udevd: unknown key 'BUS' in /etc/udev/rules.d/70-lego.rules:3
udevd: invalid rule '/etc/udev/rules.d/70-lego.rules:3'
/dev/sda5: clean, 913656/9003008 files, 31369360/35985592 blocks (check deferred; on battery)
* Starting bluetooth daemon?[154G[ OK ]
* Starting CUPS printing spooler/server?[154G[ OK ]
(when attempting to boot, there is a pause after "Begin: Running /scripts/init-bottom ... done.")
I don't know if this information will be useful, but if anyone has any suggestions as to what i could do, then that would be greatly appreciated.