Sounds like an ICQ adPopper. May be wrong, but if this only happens when you use ICQ and does not happen when you use MSN 6 or something else than yes it is written for ICQ. Uninstall ICQ and re-install after a reboot. Do you know how to edit the registry for ICQ? It may be necessary to edit the registry as some of the ICQ poppers nest a little code inside the egistry that can be safely deleted. Editing the registry is tricky if you have never done it before. Make a backup of the registry if you plan on editing it.