Unreliable Fedora 7, Mysterious Crashes

[David Hough]

I'm trying to work out what's wrong with one of my Fedora 7 systems. It
suffers random seizures, sometimes completely locking up, other times
apparently suffering partial lock-ups of one or two windows (as in they
won't update the screen when clicked but others still work), followed
shortly by a complete lock-up. Sometimes when locked up I can still ping
it, although attempting ssh gets in but never provides a prompt (but see
below). On reboot there's no clue in the syslog. The previous FC6
installation was rock-solid. Running a Xen kernel or VMWare (not on a
Xen kernel) seems to guarantee a crash much faster than if I don't run
either.

Initial thoughts were about the Evil nVidia Binary Driver, but I swapped
the graphics card for an ATI one and I still get lock-ups, so
uninstalling the nVidia driver didn't fix it. I've left it running
memtest overnight and it was quite happy.

Another clue this morning was that I did manage to get an ssh shell from
another machine, but it then objected to various commands with an
input/output error. 

The machine spec is Fedora 7 on a 2.4GHz Core 2 Duo running on an Abit
AB9 Pro motherboard. 4GB RAM, currently an ATI HD2600 graphics card,
previously an nVidia GS7600 card. Three SATA drives (independent, no
RAID), a SATA DVD and a Brainbox dual serial card. It's been through
several kernels with the problem, currently claiming to be
2.6.22.5-76.fc7 #1 SMP Thu Aug 30 13:47:21 EDT 2007 and everything else
maintained using yum update. System temperatures seem to be fine, CPU
runs about 50C even when exercised.

I have Fedora 7 on a Dell laptop and an Athlon machine and they're both
quite happy. I still sort of suspect the graphics driver but have no
real proof of it.