My Dell Poweredge 2200 has a ATI Mach64 264VT PCI 1mb video controller built
into the board. This system was  running xwindows KDE fine under Slackware 9.0.
Now that I upgraded to Slackware 10.0 and with it Xorg 6.7.0 the video
controller is no longer supported under xwindows. The console video was perfect.
The first time I tried startx my system spontaneously did a hard reboot. This
never happened again. Most of the times I entered startx the system would start,
and my monitor would reset and go blank. Ctrl+Alt+F2, Ctrl+Alt+Backspace,
Ctrl+Alt+'+', none worked. The only thing I could do is Ctrl+Alt+Delete. It was
as if the system failed to load and returned to the console mode without the
video controller processing it. Under some more general and minimal xorgconfig's
it would fail to load xwindows and the video processor would drop back to the
console. Under every circumstance I would have this error in the logs.

"XIO: fatal IO error 104 (Connection reset by peer) on X server":0.0" after 0
requests (0 known processed) with 0 events remaining."

Tried multiple config's but nothing worked. Added a ATI Rage Pro Turbo PCI 4mb
and xwindows is running fine now.