Well, I decided to try out KDE4 last night, install went smoothly from Synaptic. Now when turning on the PC, I tried logging in with KDE 4.2, got logged in normally. Then the screen started to flicker about every 15 seconds, and a Pidgin window will randomly pop up, but it is not usable. I just can't get past this state, and I'm using Gnome currently.
I have my suspicions that this is due to me installing a driver called ATI/AMD proprietary FGLRX graphics driver, after I installed it, I rebooted and started having this problem. I looked at my KDE folder, found out there was two files corrupt (according to Nautilus), the files were called Socket-username-desktop and tmp-username-desktop. I deleted those two, logged back in on KDE, got the same error.
My specs are:
Ubuntu 9.04 jaunty
Kernel Linux 2.6.28-11-generic
Hardware:
3GB RAM.
AMD Phenom 9500 Quad-Core Processor

I wasn't 100% sure where to put this into, feel free to move it.

Is a new user affected? I strongly suspect an incompatibility between the new graphics drivers and infrastructure KDE uses ( 3D compositing for instance )

bcooksley wrote:Is a new user affected? I strongly suspect an incompatibility between the new graphics drivers and infrastructure KDE uses ( 3D compositing for instance )

Disabled the driver, working perfectly now.
Any suggestions on how to get it to work with the driver enabled?

Unfortunately I have no idea, except to ensure the refresh rate is set correctly, that ( if present ) any "RandR" related entries in System Settings > Advanced > Service Manager are disabled, and try disabling 3D effects if enabled ( Alt + Shift + F12 )