Media Sharing Issue

I have notived that I am having Iregular problems with sharing media via a
wireless network.

I have the following network setup

CQ60, CQ40 & CQ50 Presario Laptops with Windows Vista Home Premium.
NEC Desktop with Vista Home Basic
Wireless Router with the Internet and network setup through the desktop.

Situation is as follows
NEC : Media sharing avalible and shown in media player
CQ50 : No media player sharing listed for other computers on network

All Computers can access network shared files and Internet.

What I have tried
Clear the network media sharing list - FAIL
Reset Network including router - FAIL
Test Internet Connection on all systems - PASS
Windows Firewall Reset - FAIL


Hope this helps, thanks