…it begins displaying the KDE startup screen then displays some broken green diagonal lines and the computer locks up. If I boot with the “failsafe” choice…
…KDE starts normally. Yes I have Nvidia graphics, but nouveau has worked acceptably in 12.2. Any suggestions where I should start the problem diagnosis?
In the section under “[Compositing]” check for a line beginning “Enabled=”, and set that to “Enabled=false”. You can add that line if it is not already there.
Then try again with nouveau and normal booting.
That changes forces desktop effects to OFF.
I have an older system with radeon graphics, where I needed to do that with Beta1, though with RC1 I could actually login to KDE and set desktop effects of with “Configure Desktop”.
My system with nvidia graphics is doing reasonably well with nouvea - on balance, I think it is better than in earlier versions.
Having typed the above, I note my bug report was on an NV34 graphic device (FX5200) while your GeForce 6100 is in the NV4x series … so this could be a different problem ? From the ‘man nouveau’ page for supported drivers: