Comment 0 for bug 1010981

Computer does not shut down, but instead merely freezes at the graphical splash screen while remaining powered on, with monitor, fans, and all other hardware still running. I've attempted the following, all with no success:

- Issuing halt, poweroff, halt -P, shutdown -h/-H/-P, and every other conceivable variation thereof from a terminal. Have also attempted these commands from a tty after killing X.

- Graphical shutdown from unity panel. Have also tried this at login screen.

- Have attempted to disable various services and kernel modules that have been implicated in other bug reports complaining of similar issues (namely, laptop-mode, acpi-support, proprietary fglrx driver, networking, and misc. others).

- Various suggestions from Ubuntu forums (editing /etc/default/halt, updating grub with various different arguments to GRUB_CMDLINE_LINUX_DEFAULT, disabling network-manager service prior to attempting shut down, and others).

This shut down malfunction happens invariably and with total predictability. Oddly, rebooting does initially appear to work, but when computer powers back on, the OS fails to load and instead hangs at a blank, purple screen (without the typical Ubuntu logo).

Other relevant info:

- Computer is an Acer Aspire 5560-7402 laptop.

- Ubuntu is the sole OS, installed recently with default/automatic partitioning settings, using whole disk.

- uname -srvmpio output:
Linux 3.2.0-24-generic #39-Ubuntu SMP Mon May 21 16:52:17 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux (please note that the problem began immediately after installation, i.e., before upgrade from 3.2.0-23-generic kernel).

- lsb_release -rd output:
Description: Ubuntu 12.04 LTS
Release: 12.04