Cannot do KDE Graphic login

[DB]

Hi all,

Yet again a problem!

I've been running F14 64 bit now for about a month, mainly without 
problem... until yesterday afternoon.....  I did a yumex update, 
installed a few apps, then poof... stuck!

Firstly, trying to reboot, it shows the F14 blue screen with the acorn 
thingy in the middle, then goes black with a flashing cursor in the top 
left hand corner, the nix - nada - nowt.

So using this F13 installation on anothe HDD, went in and modified 
inittab from 5 to 3, can now boot to a CLI screen & run most 
non-graphical things.

Try to startx but it comes up as "no devices found" waits a few seconds 
then gives me my prompt back. Same is true if I first do an su.

So the question is..... how do I get my KDE screen back - preferably 
without reinstalling???

As ever, enormous thanks for any help!!

Dave

F14 64 bit, KDE