[CentOS] Hosed by 4.2

Hi,

I have been using Centos since 3.0. I have been upgrading 
regularly without any major problem.

4.1 to 4.2 has been a total disaster.

I ran yum update, it went through and a couple of hours later I 
rebooted and X froze with the screen just being just fuzz 
[regular rectangles, orange, green...] and the keyboard froze. 
Could not do a alt-ctrl-backspace, nor a Alt-F1-6 nor Alt-Ctrl-Del.

I have a ATI9200 with a Samsung 710N [It only works at 1240x1024 
@ 60Hz, it will not work at any other frequency]

This is the same hardware as I was running with 4.1.

I had to reinstall 4.1, now I cannot run yum update to get the 
security updates, it tries to upgrade to 4.2.

1. Is there a way to just get the updates for 4.1 and not 4.2
2. Any suggestion on what went wrong with X. It's not just the 
frequency display because the keyboard also froze.

Thanks