Synchronizing Problems

I previously had a file on a server that I synchronized
to my laptop. However, the server was moved (and it's IP
changed). However, my computer continues to try to
synchronize with the file and since it can't find it, it
keeps locking up while trying. I want to remove the file
from my synch list, but cannot find a way to do so
(without access to the original file on the server).
Please help, as this is REALLY annoying not to be able to
stop these synching attempts.