I finally got around to revisiting the problem with updates to two xserver files causing a boot failure (“black screen of death”) on my machine.
Firstly, I tried removing the proprietary AMD video driver since I believe that the issue is related to the combination of an AMD Radeon HD6450 video card and the 64-bit version of Ubuntu 10.04 LTS that are used on my machine. The default, open-source driver allowed the computer to boot, and produced a screen display, but the screen resolution was limited to 1024×768 (rather than 1680×1050).
So, it was back to trolling the Internet for a solution and – bingo! – I found that a new driver file is available. In particular, AMD have released the AMD Catalyst™ 12.6 Proprietary Linux x86 Display Driver (amd-driver-installer-12-6-x86.x86_64.run).
Once this file was downloaded and installed the machine booted normally. Even better, running Update Manager produced a list of file updates that did not include xserver-common and xserver-xorg-core, the two previous updates that caused all the trouble! All the currently suggested updates were installed. The machine rebooted flawlessly, and the screen display was back to normal.
How do I remove the FGLRX drivers after I’ve installed them by hand?
Why isn’t Ubuntu using the open-source AMD/ATI drivers?
Installing ATI Radeon HD 6450 Drivers on Ubuntu 10.04 64-bit
AMD Catalyst™ 12.6 Proprietary Linux x86 Display Driver
File Size 101.8 MB, Revision No. 12.6, Release Date 6/28/2012