HELP NEEDED!! Do I have a router that needs taken back. Please. Any information is much needed.

I have 2 computers connected to a Linksys BEFSR41 router that's
connected to a cable modem. When I shut off the computer with a
Linksys LNE 100TX(v4) Fast Ethernet Adapter, the connection light on
the router goes out. But when I shut off the computer with a Linksys
LNE 100TX(v5) Fast Ethernet Adapter, it stays on. It stays on whether
the other computer (with the Linksys LNE 100TX(v4) Fast Ethernet
Adapter) is on or off.

I've DISABLED all Advanced properties to Linksys LNE 100TX(v5) Fast
Ethernet Adapter card (APM mode wakeup, Link Wakeup, Wake On Lan, etc.

Is there something wrong with this router? I need to know so I can
take it back before it's too late. Thanks for any help. It's deeply
appreciated.