How to kill process if X is frozen during fancy KDE4 windows effects?

[Yuri]

I run KDE4 with nvidia card. KDE4 desktop effects are on, so when window 
comes back from the icon it goes through some motion slowly blowing out 
from the icon.

Very rarely, but screen freezes during such motion. Mouse still moves, 
window that was blowing out of the icon stays in the shape of curved 
triangle. Keyboard is frozen, Ctrl-Alt-FN doesn't switch to black 
terminal. I can only connect to the host from outside and kill the 
unfortunate X-client that caused the hang. After this it works just fine 
again.

My question is: what to do if there is no other host on the net? How to 
kill the process?

Yuri