Find out the name of the NetBus-server (which is most often SysEdit.exe). Go to the tasklist and kill any suspicous process. After each kill, try connecting to port 12345 (telnet localhost 12345), and the moment you can't do that anymore you have found the NetBus-server.
Most often the NetBus-server starts every time your system (Windows) starts. Of course you can just delete the NetBus-server from your HD, but then you will get a irritating Windows-message at startup telling you that the program not could be started.
So, before deleting NetBus-server from your HD you either delete the registry-key \HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run[Name of NetBus-server] or just run "NetBus_server_name /remove" which will do the same thing. Finally, restart the computer.
The NetBus-server also consists of the KeyHook.dll file, which you probably find in the same directory (the DLL isn't able to do anything on its own). If you don't find it, someone has forgetten that it's necessary for some of the features to work properly (for example the Listen-function).