WMP 11 showing up as media device...

On my home network I have an XP Pro sp3 machine, a Vista Ultimate sp2 32 bit
machine and a Vista Ultimate sp2 64 bit machine. The network is a wireless
network implemented with a Linksys WRT160N WAP/Router connected to a Comcast
cable modem. The 32 bit Vista machine connects directly to the switch via
Ethernet cable and the other two connect wirelessly.

The network is a private network and all of the machines use the same work
group name. All three machines have McAfee antivirus software and have the
Windows firewall turned on. Media sharing is turned off on all three.

On every one of them, the Network display, grouped by category, shows all
three computers, the Router as a Network Infrastructure device and a Media
Device using the same name as the 32 bit Vista machine.

I've tried turning media sharing on and then turning it off but it makes no
difference. In fact, if you click on it on the machine that it belongs to
it brings up the media sharing dialogue box. Nothing is shared and when you
cancel that box it brings up WMP11. In fact, properties reveals that it is
the WMP 11 player. If you click on it on one of the other machines it will
tell you that the owner must give you access to their library.

Can anyone tell me why WMP is showing up as a media device on the network
and how I can get rid of it?

Thanks in advance,

Howard