Ubuntu Installation :: 10.04 Login Loop With VIA Video?

I have a box built by a local shop (AMD Sempron 2400+, 1.? gig RAM). It used to have XP on it, but I replaced that with 9.10. I tried installing 10.04 from CD and encountered the login loop problem many others have experienced. I had it working once when I re-installed 9.10 and then ran the upgrade to 10.04. I got the login loop that had music up to the cymbal crash, which was clipped near the end. I tried the recommendation to switch to a command line terminal, log in, run sudo dpkg-reconfigure gdm, and then restart gdm. It worked, and I should have left well enough alone. However, I thought that it would be cleaner to install from the CD. Unfortunately, when I got to the login screen I only got a blank screen when trying <ctrl><alt><F1> (or <F2, etc). <ctrl><alt><F8> took me back to the login screen where I still encounter the login loop.

I also tried the recommendation to run the install with the F6 parameter nomodset selected. That resulted in loosing the music during the login loop, although I've discovered that sometimes it's simply because the sound is starting out muted.

Another recommendation was to drop into GRUB when first powering up. It took me a while, but I finally found out that one must hold down the shift key on power up to get to GRUB. While that did let me log in to a command line screen, running dpkg-reconfigure gdm did not work, this time. Neither did the idea of editing the GRUB command line to replace quiet splash with nomodeset.

I have read many posts on this forum talking about this problem as it applies to Nvidia or ATI graphics cards. Has anyone had any experience with the VIA video built into a motherboard? Running lshw -C Display while booted from the 9.10 CD says that I have a VIA KM400/KN400/P4M800 [S3 UniChrome] video system.

A recommendation from one of my local PLUG friends was to revert to an earlier video driver that works. Is this possible? Can I take the video driver from 9.10 and use it for 10.04? If so, how do I find it -- what's it called, where is it, what is the 10.04 driver called, and where is it, and can I just change the name of 9.10's driver (if it is different from 10.04's)? If it isn't obvious that I really don't know how this level of things work, let me confess that I don't.