I've no idea what video drivers are in place, but the systems are live.
One way is to have a quick look in the main KMenu > More Applications > Configuration to see if you have NVIDIA Display Settings - and that will show which NVidia driver and x.org versions you are running (along with some other info) - see screenshot
Well, I was wrong... not all that unusual.
The would be Myth machine (with an Nvidia 6200 video card added for the TV out) is fully updated to 2011, but acts strangely. (Per your suggestion, menotu, I checked the installed video driver: It is running Nvidia 275.09.07 (current)). The strangeness comes in with Synaptic, which operates by jerks. It won't glide smoothly through the list of programs while the slider is being moved. I have to move the cursor to the approximate position where I think the program might be, then wait to see what part of the alphabet shows up. Then the mouse scroll wheel may be used to locate the desired package.
The garage machine (which I thought was fully updated because the huge list of upgradeable programs went away with a kernel update) still has sound, and still shows pclos 2010. The huge list of needed upgrades is back.
The office machine is showing pclos 2011 and has no sound. I think this is a function of the current X window setup/ chipset drivers.
All 3 computers have dual threading 2.8GHz P4s, 800MHz front side bus with 2Gigs of ram on an Intel board with integrated sound and video. The motherboards all use the i865 chipset.
About the i915 drivers...
Anyone know how to make them work with my hardware, or force the use of the proper driver off my 2010.12 CD? Which package(s) need to be messed with / held back while updating from a fresh 2010.12 install?
I understand that eventually not upgrading to i915 could kill the operating system.
On the other hand, doing the upgrade kills them right now.
Edit: All of the machines now work with updated 2010-12
Tex and his boys must have been busy: Thanks everyone.