Hi,
it looks like the headset has the incorrect settings with 'Default communication device'.
Try highlighting it with your cursor and see if the 'set default' button becomes available below.
If it does click on the arrow and set it to default only.
I'm not sure if this will make the headset the only default device or not but if it does simply highlight the speakers and set them to default.
Of course there's always 'system restore' but that seems a little heavy handed at the moment. Let us know how you get on.