(I'm on a Mac, BTW.)
I have a Linksys WRT54G2 that has been serving as our Wi-Fi hub for some time. We love it.
Today I bought a Blu-ray players with Internet capabilities (streaming NetFlix), and plugged its Ethernet port straight into the back of the WRT54G2.
It seems I can't use both at the same time.
As soon as I start using the Blu-ray player, the Wi-Fi connection is immediately dropped on all other connected devices and the SSID is no longer visible.