X won't start on F14 - I've run out of ideas!

[Claude Jones]

This is an F14 box with all the latest patches
It has an nVidia GeForce 8400 GS video card
It had been running the proprietary nVidia driver from rpmfusion
About two weeks ago, after some updates which unfortunately I didn't 
take note of, X would no longer start (long story)
Things I've tried:
I removed the nVidia driver and de-blacklisted nouveau in grub.conf and 
verified that it was now loading with lsmod - and that nVidia and none 
of its parts were still trying to load
Deleted xorg.conf
Tried switching desktop manager from KDE to Gnome
Tried booting to an earlier kernel
Googled endlessly and tried various other things from those searches - 
too numerous to remember now
Looked at the messages, Xorg.0.log, and boot.log files but could find no 
smoking gun

Right now, if I boot into runlevel 3 and run startx I get some brief 
activity - the screen goes black, then flashes the blue splash screen 
momentarily, then returns4 to the command prompt = the messages returned 
say little as to why it failed

I can boot from a live Fedora 14 CD and the machine comes up fine and 
the display works

I actually suspect this may be a mouse issue - I seem to remember such a 
solution to a similar problem, though I can't seem to find it with 
google so far - why I suspect this is because the display does work on 
boot, displaying the first splash screen with the option to choose/edit 
the kernel - then the progress indicating blue bar at the bottom of the 
screen; the screen does attempt to display the login screen for a brief 
instant when I run startx; at no time does the mouse cursor appear - I 
seem to remember that it would be available even when booting into 
runlevel 3 when it was working correctly (am I recalling that right?)

ideas on what to try next welcome - I'll post any log excerpts anyone 
thinks could be useful

-- 
Claude Jones	
Brunswick, MD, USA