why kill them all?
Go to a vt (lets say: ttyS2, to do that, hitt ctrl+alt+F2, to get back to KDE and X hit, ctrl+alt+f5, could be F1, F3, F4... be patient it might take a few seconds for the screen to wake) and type ps -A look for the name of what is bothering you.

if i had a frozen centericq i would do
ps -A
output would be a looooong list (i have some 6 xterms), here is a part of that output.
Code:
 
  652 ?        00:00:00 fvwm95
  686 ?        00:00:40 gkrellm
  687 ?        00:00:00 FvwmTaskBar
  688 ?        00:00:00 FvwmButtons
  692 ?        00:00:00 xterm
  702 pts/0    00:00:01 centericq
then a
Code:
kill 702
would do just that, kill the process with number 702. it might be that it won't die, hmmm, ok.
Code:
kill -9 702
that would work. if not, hmmm. ok lets pretend it did not work, check if something keeps it alive (is above it in the ps tree)
ps -aux then kill anythng assosiated with centericq, and ofcource centericq).
in this case Xterm.
oe 652 0.0 0.6 2808 1532 ? S 16:23 0:00 fvwm95
oe 686 0.3 2.5 10276 6112 ? S 16:23 0:41 gkrellm
oe 687 0.0 0.5 2532 1216 ? S 16:23 0:00 /usr/X11R6/lib/X1
oe 688 0.0 0.5 2520 1216 ? S 16:23 0:00 /usr/X11R6/lib/X1
oe 692 0.0 1.0 5036 2620 ? S 16:23 0:00 xterm -T centeric
oe 694 0.0 0.4 2092 1024 ? S 16:23 0:00 /bin/sh /usr/lib/
oe 702 0.0 1.8 7648 4380 pts/0 S 16:23 0:01 centericq
now do
Code:
 kill -9 692 702
if it survives this it is a Zombie process (yes it is the actuall name) and canot be killed short of reboot.