Jaunty -> Karmic upgrade: Cannot log in any more

Greetings,

  I have an ASUS motherboard which thus far has been running Kubuntu Intrepid and Jaunty fine with no issues. I upgraded to Karmic yesterday and suddenly found that I cannot log into my system any longer. I enter my username and password and try to log in. KDE attempts to start loading and gets to the "loading" screen with the five icons. The HDD icon lights up and then the screen flickers and I'm back at the login screen. Sometimes, it progresses past this stage and then kicks me back to the login screen.

  I can log in fine via a terminal (with ctrl + alt + f1). I have updated all my packages with apt.

  Things that I have tried so far (and did not work):

* Renamed my .kde directory to .kde.bak and tried logging in. This fails, but I do see a .kde directory being created.
* This board has a VIA chipset and requires unichrome drivers. I'm pretty certain that I was using the openchrome drivers and had things working with Jaunty. I tried reinstalling these via apt.
* I've tried using xorg -configure to create a template xorg.conf file and used it.
* With the above xorg.conf file, I've tried specifying vesa as the driver. X complained about vesa not supporting 24 bit and crashed.
* I've also tried removing xserver-xorg-video-openchrome and restarting. X does not start.

I'll attach log files shortly.

I'm happy to stick around and get this solved completely. But in the interim, could somebody suggest a way to get my display back with VESA? I don't mind 640x480 resolution etc. while I try to find a solution.

Thanks.