Hardware: Compaq HP nc6000 laptop

Hi, here's my problem. I started with Kubuntu 8.04, upgraded to KDE 4.1 and loved it. Then, I installed Gnome. I also have KDE 3.5.9 -- At some point, I think after an update to the kernel, or some other, or maybe right after a Nessus scan... the computer locked up and I turned it off without shutting down properly (in KDE 4.1). I'd done this before without a problem, but this time KDE4 wouldn't load again. I have no problems loading Gnome or the older KDE.

I've been working on this for more than a week, and I've learned a lot, but I've tried everything I can think of... I am relatively new to linux, but not afraid of the command line. I have moved ~/.kde4 out of the way, tried using GDM vs. KDM -- oh, and BTW, KDM-KDE4 crashes and drops me to a text login -- I've removed and reinstalled everything related to KDE4. And still, it doesn't work.

The error log (when using KDM-KDE4) says 'received an unknown command -2 from greeter'

When trying to load KDE4 from KDM, the error that comes up is 'Call to lnusertemp failed (temporary directory full?) Check your installation'

Also, /usr/lib/kde4/etc/kde4/kdm/kdmrc doesn't seem to exist, though I don't see how this could be causing the problem.

I have tried emptying /tmp, thinking maybe it was just a problem with KDM-KDE4, even tried re-creating my user account -- I've read through everything I could find on the web and I'm beginning to think it's a display problem. There's one strange thing which points me to this: When trying to load KDE4, when the screen changes (or refreshes), I can actually see the black shiny icon screen loading somehow 'beneath' the ugly bright blue kdm screen where the error comes up.

Could I be having this problem because it's trying to open a display that's already open? And why wouldn't the other GUIs have this problem? (I even tried Xfce but didn't like it... maybe I do have too many desktop interfaces, but next I'm thinking Enlightenment.) I really like KDE 4.1 and had it completely configured. There are a number of other problems I have yet to work out, but first things first. Any ideas? I'm in over my head on this and any help would be really appreciated.