Like the title says, everything was great..then I upgraded my kernel as it came down from kubuntu backports last night. Since then it seems I am onle able to use GTK apps. When I launch kde apps. they just sit there trying to load in the icon task manager but doesn;t ever start. My first solution was to use update-burg and boot an older kernel. Booting the old kernels were no use but my KDE apps from my last session did open at that point. I just could not start new instances. I then tried removing contents from certain directories(I forgot the specific ones but should be nothing big) trying to delete the old session. Finally I edited ksomethingrc(forgot the name) leaving only screen 1(kwin) in the file and deleting all the temp files referenced in that file. Seems I am able to boot a clean session besides an instance of kate. So I tried other kenrels and still no luck. How can I get KDE apps working again?'

UPDATE: Booting in to rescue mode for the latest kernel just hangs after detecting USB ports. The only USB periphrasis, besides mouse and keyboard, is my printed.

All 3 kernels hang when trying rescue mode. In Kubuntu I dropped down to TTY2 and installed xterm but it doesnt seem to want to launch.

Finally fixed it! I had to drop down to TTY2(CTRL+ALT+F2), log in, then run "pkill kate" so it seems kate was misbehaving preventing anything KDE related from starting.

For Kate itself, you may find it helpful to clear the Kate session files, located at ~/.kde4/share/apps/kate/