The Radeon 7000 and the X.org radeon driver have had some well publicized difficulties since CentOS 4.2 (aka RHEL4U2). In short, the 7000 would hang miserably, often completely killing the console. See, e.g.,
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=170008
On Nov 29, 2005, Red Hat's Mike Harris announced the testing release of xorg-x11-6.8.2-1.EL.13.21, which ended up solving the problems with my video subsystem. That ticket was later marked closed with an errata release of the xorg-x11 packages:
http://rhn.redhat.com/errata/RHBA-2006-0072.html
I installed that upgrade (xorg-x11-6.8.2-1.EL.13.25) when it was made available via yum, but never not around to rebooting until the recent 4.3 release.
My (PCI, not AGP) Radeon 7000 went on strike again! The console crashes aren't as fatal this time around -- the screen is a mess, but the keyboard and mouse still respond to input (though I can't see what I'm typing) -- but they still render the console unusable.
For now, I've reinstalled the radeon_drv.so from Mike Harris' xorg-x11-6.8.2-1.EL.13.21 interim release -- which, thankfully, I've kept around, because they are no longer available in Mike's chunk of people.redhat.com -- and that's solved the problem.
I'll try to send a real bug report once I can isolate what may have changed between .21 and .25, but for now I thought I'd just send a general problem description.
-- Paul Heinlein heinlein@madboa.com