Hey Moira,

You can forget about the MAC filtering, it'll cause more grief than benefit as MAC Spoofing isn't too difficult to achieve. Just ensure you use the WEP2 with 128bit option instead and use MiX3duP passwords.

I would reset the router to a default settings and ensure the router uses the standard 192.168 as appose to a deviant of it. I never had good luck with changing the IP assignment and this could be causing the problem.

There may be an option inside the router that mentions not to share internet connections to Wireless, as a security feature. This way, the wired PCs can surf the web, share files and play LAN games, while the Wifi connections can only share files and play LAN games.

From my personal experience with Wireless routers, Doing a search for firmware updates tend to help, as I had problems with my own DLink router two weeks ago. After the firmware update everything worked great.

Hope any of this helps?