problem with CentOS and X

[Buz Davis]

First, let me say this is sorta a continuation of some previous threads 
starting with attempts to install Fedora 8.  Thanks to Rick Stevens, Bob 
McClure, et al. for their attention.  It turned out that I had a machine 
capable of running modern stuff, just obscured by a thick layer of XP.  
I have successfully installed CentOS 5.3 on it.  In the process of my 
attempts I also bought a second hand box that turned-out to have an 
i686, though apparently a slow one.  My question involves that box.  It 
apparently runs at 550 Mhz, and now has plenty of disk space
and memory (just under a gig of memory, and it survived one pass of 
memtest86 without error).  I have tried to install CentOS on this box, 
too, but cannot get X to run.  I get all the way to the blue screen with 
the doily on it, but no desktop icons. (Icons are on the bars at top and 
bottom, but there is no sign of Home, Trash, and computer on the blue 
desktop).
I have tried Gnome, KDE, and another whose name escapes me at the moment 
but is supported by switchdesk.

I have also compared the tail ends of /var/log/Xorg.0.log on the two 
machines, the one that works and the one that doesn't.  They both end in 
the same place.

I suspect that the older machine just doesn't have the horsepower for 
CentOS 5.3, and next intend to try an older version of CentOS.  But 
before doing so I wanted to ask if there was something I should do 
first, like examine some other log file or a kernel parameter to try.  I 
would like to get 5.3 with X going if possible.  I would appreciate any 
suggestions.